72191920 has 40 divisors (see below), whose sum is σ = 168359760. Its totient is φ = 28788480.

The previous prime is 72191909. The next prime is 72191923. The reversal of 72191920 is 2919127.

It is a tau number, because it is divible by the number of its divisors (40).

It is not an unprimeable number, because it can be changed into a prime (72191923) 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 7 ways as a sum of consecutive naturals, for example, 29130 + ... + 31510.

It is an arithmetic number, because the mean of its divisors is an integer number (4208994).

Almost surely, 2^72191920 is an apocalyptic number.

It is an amenable number.

72191920 is an abundant number, since it is smaller than the sum of its proper divisors (96167840).

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

72191920 is a wasteful number, since it uses less digits than its factorization.

72191920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2773 (or 2767 counting only the distinct ones).

The product of its (nonzero) digits is 2268, while the sum is 31.

The square root of 72191920 is about 8496.5828425315. The cubic root of 72191920 is about 416.3860752645.

The spelling of 72191920 in words is "seventy-two million, one hundred ninety-one thousand, nine hundred twenty".