78888398661 has 16 divisors (see below), whose sum is σ = 120901761600. Its totient is φ = 50778738864.

The previous prime is 78888398647. The next prime is 78888398723. The reversal of 78888398661 is 16689388887.

It is not a de Polignac number, because 78888398661 - 2²⁶ = 78821289797 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 78888398661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78888398621) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 50374951 + ... + 50376516.

It is an arithmetic number, because the mean of its divisors is an integer number (7556360100).

Almost surely, 2^78888398661 is an apocalyptic number.

It is an amenable number.

78888398661 is a deficient number, since it is larger than the sum of its proper divisors (42013362939).

78888398661 is a wasteful number, since it uses less digits than its factorization.

78888398661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 100751505 (or 100751499 counting only the distinct ones).

The product of its digits is 222953472, while the sum is 72.

The spelling of 78888398661 in words is "seventy-eight billion, eight hundred eighty-eight million, three hundred ninety-eight thousand, six hundred sixty-one".