394564991631 has 16 divisors (see below), whose sum is σ = 530191398528. Its totient is φ = 260991629600.

The previous prime is 394564991603. The next prime is 394564991659. The reversal of 394564991631 is 136199465493.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (394564991603) and next prime (394564991659).

It is a cyclic number.

It is not a de Polignac number, because 394564991631 - 2⁷ = 394564991503 is a prime.

It is a super-2 number, since 2×394564991631² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (394564991831) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2354416 + ... + 2516426.

It is an arithmetic number, because the mean of its divisors is an integer number (33136962408).

Almost surely, 2^394564991631 is an apocalyptic number.

394564991631 is a deficient number, since it is larger than the sum of its proper divisors (135626406897).

394564991631 is a wasteful number, since it uses less digits than its factorization.

394564991631 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 168342.

The product of its digits is 18895680, while the sum is 60.

The spelling of 394564991631 in words is "three hundred ninety-four billion, five hundred sixty-four million, nine hundred ninety-one thousand, six hundred thirty-one".