72231978 has 48 divisors (see below), whose sum is σ = 180986400. Its totient is φ = 19049184.

The previous prime is 72231947. The next prime is 72232001. The reversal of 72231978 is 87913227.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 5628 + ... + 13271.

It is an arithmetic number, because the mean of its divisors is an integer number (3770550).

Almost surely, 2^72231978 is an apocalyptic number.

72231978 is a gapful number since it is divisible by the number (78) formed by its first and last digit.

72231978 is an abundant number, since it is smaller than the sum of its proper divisors (108754422).

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

72231978 is a wasteful number, since it uses less digits than its factorization.

72231978 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18931 (or 18924 counting only the distinct ones).

The product of its digits is 42336, while the sum is 39.

The square root of 72231978 is about 8498.9398162359. The cubic root of 72231978 is about 416.4630760761.

The spelling of 72231978 in words is "seventy-two million, two hundred thirty-one thousand, nine hundred seventy-eight".