397904381 has 4 divisors (see below), whose sum is σ = 454747872. Its totient is φ = 341060892.

The previous prime is 397904371. The next prime is 397904383. The reversal of 397904381 is 183409793.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-397904381 is a prime.

It is a super-2 number, since 2×397904381² = 316655792837986322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (397904383) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 28421735 + ... + 28421748.

It is an arithmetic number, because the mean of its divisors is an integer number (113686968).

Almost surely, 2^397904381 is an apocalyptic number.

It is an amenable number.

397904381 is a deficient number, since it is larger than the sum of its proper divisors (56843491).

397904381 is an equidigital number, since it uses as much as digits as its factorization.

397904381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 56843490.

The product of its (nonzero) digits is 163296, while the sum is 44.

The square root of 397904381 is about 19947.5407256133. The cubic root of 397904381 is about 735.5173250331.

The spelling of 397904381 in words is "three hundred ninety-seven million, nine hundred four thousand, three hundred eighty-one".