78991560 has 96 divisors (see below), whose sum is σ = 261144000. Its totient is φ = 20701824.

The previous prime is 78991553. The next prime is 78991579. The reversal of 78991560 is 6519987.

78991560 is a `hidden beast` number, since 7 + 89 + 9 + 1 + 560 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 19381 + ... + 23099.

It is an arithmetic number, because the mean of its divisors is an integer number (2720250).

Almost surely, 2^78991560 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 78991560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (130572000).

78991560 is an abundant number, since it is smaller than the sum of its proper divisors (182152440).

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

78991560 is a wasteful number, since it uses less digits than its factorization.

78991560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3795 (or 3788 counting only the distinct ones).

The product of its (nonzero) digits is 136080, while the sum is 45.

The square root of 78991560 is about 8887.7196175397. The cubic root of 78991560 is about 429.0687616972.

The spelling of 78991560 in words is "seventy-eight million, nine hundred ninety-one thousand, five hundred sixty".