391911945 has 64 divisors (see below), whose sum is σ = 671846400. Its totient is φ = 194754560.

The previous prime is 391911929. The next prime is 391911953. The reversal of 391911945 is 549119193.

It is not a de Polignac number, because 391911945 - 2⁴ = 391911929 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 391911897 and 391911906.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2051800 + ... + 2051990.

It is an arithmetic number, because the mean of its divisors is an integer number (10497600).

Almost surely, 2^391911945 is an apocalyptic number.

It is an amenable number.

391911945 is a deficient number, since it is larger than the sum of its proper divisors (279934455).

391911945 is a wasteful number, since it uses less digits than its factorization.

391911945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 370.

The product of its digits is 43740, while the sum is 42.

The square root of 391911945 is about 19796.7660237727. The cubic root of 391911945 is about 731.8063385532.

The spelling of 391911945 in words is "three hundred ninety-one million, nine hundred eleven thousand, nine hundred forty-five".