391479992640 has 504 divisors, whose sum is σ = 1494042732000. Its totient is φ = 94008330240.

The previous prime is 391479992633. The next prime is 391479992647. The reversal of 391479992640 is 46299974193.

391479992640 is a `hidden beast` number, since 39 + 1 + 479 + 9 + 92 + 6 + 40 = 666.

It is an interprime number because it is at equal distance from previous prime (391479992633) and next prime (391479992647).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391479992647) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 37282111 + ... + 37292609.

It is an arithmetic number, because the mean of its divisors is an integer number (2964370500).

Almost surely, 2^391479992640 is an apocalyptic number.

391479992640 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 391479992640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (747021366000).

391479992640 is an abundant number, since it is smaller than the sum of its proper divisors (1102562739360).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

391479992640 is a wasteful number, since it uses less digits than its factorization.

391479992640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10651 (or 10627 counting only the distinct ones).

The product of its (nonzero) digits is 26453952, while the sum is 63.

The spelling of 391479992640 in words is "three hundred ninety-one billion, four hundred seventy-nine million, nine hundred ninety-two thousand, six hundred forty".