78791640 has 32 divisors (see below), whose sum is σ = 236375280. Its totient is φ = 21011072.

The previous prime is 78791621. The next prime is 78791663. The reversal of 78791640 is 4619787.

It is a junction number, because it is equal to n+sod(n) for n = 78791592 and 78791601.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 328179 + ... + 328418.

Almost surely, 2^78791640 is an apocalyptic number.

It is an amenable number.

78791640 is an abundant number, since it is smaller than the sum of its proper divisors (157583640).

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

78791640 is a wasteful number, since it uses less digits than its factorization.

78791640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 656611 (or 656607 counting only the distinct ones).

The product of its (nonzero) digits is 84672, while the sum is 42.

The square root of 78791640 is about 8876.4655128041. The cubic root of 78791640 is about 428.7064787088.

The spelling of 78791640 in words is "seventy-eight million, seven hundred ninety-one thousand, six hundred forty".