78172816878 has 64 divisors (see below), whose sum is σ = 187150528320. Its totient is φ = 24044138496.

The previous prime is 78172816859. The next prime is 78172816937. The reversal of 78172816878 is 87861827187.

It is a super-2 number, since 2×78172816878² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1986126 + ... + 2025102.

It is an arithmetic number, because the mean of its divisors is an integer number (2924227005).

Almost surely, 2^78172816878 is an apocalyptic number.

78172816878 is a gapful number since it is divisible by the number (78) formed by its first and last digit.

78172816878 is an abundant number, since it is smaller than the sum of its proper divisors (108977711442).

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

78172816878 is a wasteful number, since it uses less digits than its factorization.

78172816878 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41858 (or 41852 counting only the distinct ones).

The product of its digits is 16859136, while the sum is 63.

The spelling of 78172816878 in words is "seventy-eight billion, one hundred seventy-two million, eight hundred sixteen thousand, eight hundred seventy-eight".