72691664 has 20 divisors (see below), whose sum is σ = 142135620. Its totient is φ = 36011520.

The previous prime is 72691639. The next prime is 72691667. The reversal of 72691664 is 46619627.

It can be written as a sum of positive squares in 2 ways, for example, as 56370064 + 16321600 = 7508^2 + 4040^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72691667) 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 3 ways as a sum of consecutive naturals, for example, 19097 + ... + 22584.

It is an arithmetic number, because the mean of its divisors is an integer number (7106781).

Almost surely, 2^72691664 is an apocalyptic number.

It is an amenable number.

72691664 is a deficient number, since it is larger than the sum of its proper divisors (69443956).

72691664 is a wasteful number, since it uses less digits than its factorization.

72691664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41798 (or 41792 counting only the distinct ones).

The product of its digits is 108864, while the sum is 41.

The square root of 72691664 is about 8525.9406519164. The cubic root of 72691664 is about 417.3446688108.

The spelling of 72691664 in words is "seventy-two million, six hundred ninety-one thousand, six hundred sixty-four".