838

838 = 2 x 419. It is a palindrome with exactly two prime factors (A046328). Both prime factors are distinct Sophie Germain primes (A157344). The sum of its prime factors is a prime (A108605): 2 + 419 = 421.

838 is a happy number.

838 and 838² = 702244 have the same digit sum (A058369).

838 is the number of primes between 140,000 and 150,000 (A038824).

838 is the integer part of the surface area of a regular tetrahedron with edge length 22 (A171972).

Source: On-Line Encyclopedia of Integer Sequences