391478064768 has 640 divisors, whose sum is σ = 1421107248000. Its totient is φ = 104485552128.

The previous prime is 391478064737. The next prime is 391478064827. The reversal of 391478064768 is 867460874193.

391478064768 is a `hidden beast` number, since 3 + 91 + 4 + 78 + 0 + 6 + 476 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (63).

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 100660968 + ... + 100664856.

It is an arithmetic number, because the mean of its divisors is an integer number (2220480075).

Almost surely, 2^391478064768 is an apocalyptic number.

391478064768 is a gapful number since it is divisible by the number (38) 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 391478064768, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (710553624000).

391478064768 is an abundant number, since it is smaller than the sum of its proper divisors (1029629183232).

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

391478064768 is a wasteful number, since it uses less digits than its factorization.

391478064768 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4014 (or 3993 counting only the distinct ones).

The product of its (nonzero) digits is 48771072, while the sum is 63.

The spelling of 391478064768 in words is "three hundred ninety-one billion, four hundred seventy-eight million, sixty-four thousand, seven hundred sixty-eight".