72178731 has 12 divisors (see below), whose sum is σ = 104390208. Its totient is φ = 48058224.

The previous prime is 72178723. The next prime is 72178783. The reversal of 72178731 is 13787127.

It is a happy number.

It is not a de Polignac number, because 72178731 - 2³ = 72178723 is a prime.

It is a super-2 number, since 2×72178731² = 10419538417540722, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (72178831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3121 + ... + 12413.

It is an arithmetic number, because the mean of its divisors is an integer number (8699184).

Almost surely, 2^72178731 is an apocalyptic number.

72178731 is a deficient number, since it is larger than the sum of its proper divisors (32211477).

72178731 is a wasteful number, since it uses less digits than its factorization.

72178731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10162 (or 10159 counting only the distinct ones).

The product of its digits is 16464, while the sum is 36.

The square root of 72178731 is about 8495.8066715292. The cubic root of 72178731 is about 416.3607166998.

The spelling of 72178731 in words is "seventy-two million, one hundred seventy-eight thousand, seven hundred thirty-one".