390631969 has 24 divisors (see below), whose sum is σ = 501332328. Its totient is φ = 301512960.

The previous prime is 390631939. The next prime is 390631973. The reversal of 390631969 is 969136093.

It can be written as a sum of positive squares in 4 ways, for example, as 17640000 + 372991969 = 4200^2 + 19313^2 .

It is not a de Polignac number, because 390631969 - 2²⁷ = 256414241 is a prime.

It is a super-2 number, since 2×390631969² = 305186670409633922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (390631919) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 18639 + ... + 33595.

It is an arithmetic number, because the mean of its divisors is an integer number (20888847).

Almost surely, 2^390631969 is an apocalyptic number.

It is an amenable number.

390631969 is a deficient number, since it is larger than the sum of its proper divisors (110700359).

390631969 is a wasteful number, since it uses less digits than its factorization.

390631969 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15025 (or 15018 counting only the distinct ones).

The product of its (nonzero) digits is 236196, while the sum is 46.

The square root of 390631969 is about 19764.4116785701. The cubic root of 390631969 is about 731.0087817230.

The spelling of 390631969 in words is "three hundred ninety million, six hundred thirty-one thousand, nine hundred sixty-nine".