838400391 has 24 divisors (see below), whose sum is σ = 1226117984. Its totient is φ = 551992320.

The previous prime is 838400371. The next prime is 838400399. The reversal of 838400391 is 193004838.

It is not a de Polignac number, because 838400391 - 2⁵ = 838400359 is a prime.

It is a Duffinian number.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (838400399) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 634011 + ... + 635331.

Almost surely, 2^838400391 is an apocalyptic number.

838400391 is a deficient number, since it is larger than the sum of its proper divisors (387717593).

838400391 is a wasteful number, since it uses less digits than its factorization.

838400391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2151 (or 2148 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 36.

The square root of 838400391 is about 28955.1444651896. The cubic root of 838400391 is about 942.9394896299.

The spelling of 838400391 in words is "eight hundred thirty-eight million, four hundred thousand, three hundred ninety-one".