78661013544 has 80 divisors (see below), whose sum is σ = 221032674720. Its totient is φ = 26135961120.

The previous prime is 78661013491. The next prime is 78661013609. The reversal of 78661013544 is 44531016687.

78661013544 is a `hidden beast` number, since 7 + 86 + 6 + 10 + 13 + 544 = 666.

It is a self number, because there is not a number n which added to its sum of digits gives 78661013544.

It is an unprimeable number.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 6367 + ... + 396689.

It is an arithmetic number, because the mean of its divisors is an integer number (2762908434).

Almost surely, 2^78661013544 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 78661013544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (110516337360).

78661013544 is an abundant number, since it is smaller than the sum of its proper divisors (142371661176).

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

78661013544 is a wasteful number, since it uses less digits than its factorization.

78661013544 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 390652 (or 390639 counting only the distinct ones).

The product of its (nonzero) digits is 483840, while the sum is 45.

The spelling of 78661013544 in words is "seventy-eight billion, six hundred sixty-one million, thirteen thousand, five hundred forty-four".