391021640465 has 32 divisors (see below), whose sum is σ = 483123864960. Its totient is φ = 303595928064.

The previous prime is 391021640417. The next prime is 391021640497. The reversal of 391021640465 is 564046120193.

It is a cyclic number.

It is not a de Polignac number, because 391021640465 - 2⁸ = 391021640209 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 174328634 + ... + 174330876.

It is an arithmetic number, because the mean of its divisors is an integer number (15097620780).

Almost surely, 2^391021640465 is an apocalyptic number.

It is an amenable number.

391021640465 is a deficient number, since it is larger than the sum of its proper divisors (92102224495).

391021640465 is a wasteful number, since it uses less digits than its factorization.

391021640465 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4241.

The product of its (nonzero) digits is 155520, while the sum is 41.

The spelling of 391021640465 in words is "three hundred ninety-one billion, twenty-one million, six hundred forty thousand, four hundred sixty-five".