78917172 has 12 divisors (see below), whose sum is σ = 184140096. Its totient is φ = 26305720.

The previous prime is 78917143. The next prime is 78917173. The reversal of 78917172 is 27171987.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78917173) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3288204 + ... + 3288227.

It is an arithmetic number, because the mean of its divisors is an integer number (15345008).

Almost surely, 2^78917172 is an apocalyptic number.

It is an amenable number.

78917172 is an abundant number, since it is smaller than the sum of its proper divisors (105222924).

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

78917172 is a wasteful number, since it uses less digits than its factorization.

78917172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6576438 (or 6576436 counting only the distinct ones).

The product of its digits is 49392, while the sum is 42.

The square root of 78917172 is about 8883.5337563382. The cubic root of 78917172 is about 428.9340317275.

The spelling of 78917172 in words is "seventy-eight million, nine hundred seventeen thousand, one hundred seventy-two".