72420644 has 6 divisors (see below), whose sum is σ = 126736134. Its totient is φ = 36210320.

The previous prime is 72420617. The next prime is 72420661. The reversal of 72420644 is 44602427.

It can be written as a sum of positive squares in only one way, i.e., 62884900 + 9535744 = 7930^2 + 3088^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9052577 + ... + 9052584.

It is an arithmetic number, because the mean of its divisors is an integer number (21122689).

Almost surely, 2^72420644 is an apocalyptic number.

It is an amenable number.

72420644 is a deficient number, since it is larger than the sum of its proper divisors (54315490).

72420644 is a wasteful number, since it uses less digits than its factorization.

72420644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18105165 (or 18105163 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 29.

The square root of 72420644 is about 8510.0319623372. The cubic root of 72420644 is about 416.8253538142.

The spelling of 72420644 in words is "seventy-two million, four hundred twenty thousand, six hundred forty-four".