391138560 has 216 divisors, whose sum is σ = 1425322080. Its totient is φ = 98758656.

The previous prime is 391138523. The next prime is 391138589. The reversal of 391138560 is 65831193.

It is a happy number.

391138560 is a `hidden beast` number, since 3 + 91 + 1 + 3 + 8 + 560 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 217987 + ... + 219773.

Almost surely, 2^391138560 is an apocalyptic number.

391138560 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 391138560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (712661040).

391138560 is an abundant number, since it is smaller than the sum of its proper divisors (1034183520).

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

391138560 is a wasteful number, since it uses less digits than its factorization.

391138560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1833 (or 1816 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 36.

The square root of 391138560 is about 19777.2232631378. The cubic root of 391138560 is about 731.3246480884.

The spelling of 391138560 in words is "three hundred ninety-one million, one hundred thirty-eight thousand, five hundred sixty".