78657711990 has 128 divisors (see below), whose sum is σ = 221938182144. Its totient is φ = 17589312000.

The previous prime is 78657711973. The next prime is 78657712009. The reversal of 78657711990 is 9911775687.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 6948435 + ... + 6959745.

It is an arithmetic number, because the mean of its divisors is an integer number (1733892048).

Almost surely, 2^78657711990 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 78657711990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (110969091072).

78657711990 is an abundant number, since it is smaller than the sum of its proper divisors (143280470154).

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

78657711990 is a wasteful number, since it uses less digits than its factorization.

78657711990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12966.

The product of its (nonzero) digits is 6667920, while the sum is 60.

The spelling of 78657711990 in words is "seventy-eight billion, six hundred fifty-seven million, seven hundred eleven thousand, nine hundred ninety".