78172817388 has 24 divisors (see below), whose sum is σ = 182408252208. Its totient is φ = 26056889856.

The previous prime is 78172817353. The next prime is 78172817389. The reversal of 78172817388 is 88371827187.

It is a super-2 number, since 2×78172817388² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (78172817389) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 545920 + ... + 674072.

It is an arithmetic number, because the mean of its divisors is an integer number (7600343842).

Almost surely, 2^78172817388 is an apocalyptic number.

It is an amenable number.

78172817388 is an abundant number, since it is smaller than the sum of its proper divisors (104235434820).

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

78172817388 is a wasteful number, since it uses less digits than its factorization.

78172817388 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 178993 (or 178991 counting only the distinct ones).

The product of its digits is 8429568, while the sum is 60.

The spelling of 78172817388 in words is "seventy-eight billion, one hundred seventy-two million, eight hundred seventeen thousand, three hundred eighty-eight".