78634990 has 64 divisors (see below), whose sum is σ = 168384384. Its totient is φ = 25878528.

The previous prime is 78634973. The next prime is 78634991. The reversal of 78634990 is 9943687.

It is a self number, because there is not a number n which added to its sum of digits gives 78634990.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78634991) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 251074 + ... + 251386.

It is an arithmetic number, because the mean of its divisors is an integer number (2631006).

Almost surely, 2^78634990 is an apocalyptic number.

78634990 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

78634990 is an abundant number, since it is smaller than the sum of its proper divisors (89749394).

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

78634990 is a wasteful number, since it uses less digits than its factorization.

78634990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 461.

The product of its (nonzero) digits is 326592, while the sum is 46.

The square root of 78634990 is about 8867.6372275821. The cubic root of 78634990 is about 428.4221785588.

The spelling of 78634990 in words is "seventy-eight million, six hundred thirty-four thousand, nine hundred ninety".