78632991 has 8 divisors (see below), whose sum is σ = 116493360. Its totient is φ = 52421976.

The previous prime is 78632987. The next prime is 78633011. The reversal of 78632991 is 19923687.

78632991 is a `hidden beast` number, since 7 + 8 + 632 + 9 + 9 + 1 = 666.

It is not a de Polignac number, because 78632991 - 2² = 78632987 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78632951) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1456140 + ... + 1456193.

It is an arithmetic number, because the mean of its divisors is an integer number (14561670).

Almost surely, 2^78632991 is an apocalyptic number.

78632991 is a deficient number, since it is larger than the sum of its proper divisors (37860369).

78632991 is a wasteful number, since it uses less digits than its factorization.

78632991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2912342 (or 2912336 counting only the distinct ones).

The product of its digits is 163296, while the sum is 45.

The square root of 78632991 is about 8867.5245136396. The cubic root of 78632991 is about 428.4185481851.

The spelling of 78632991 in words is "seventy-eight million, six hundred thirty-two thousand, nine hundred ninety-one".