72991575 has 36 divisors (see below), whose sum is σ = 131249040. Its totient is φ = 38776320.

The previous prime is 72991549. The next prime is 72991601. The reversal of 72991575 is 57519927.

72991575 is a `hidden beast` number, since 72 + 9 + 9 + 1 + 575 = 666.

It is an interprime number because it is at equal distance from previous prime (72991549) and next prime (72991601).

It is not a de Polignac number, because 72991575 - 2⁷ = 72991447 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 72991575.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 78966 + ... + 79884.

Almost surely, 2^72991575 is an apocalyptic number.

72991575 is a gapful number since it is divisible by the number (75) formed by its first and last digit.

72991575 is a deficient number, since it is larger than the sum of its proper divisors (58257465).

72991575 is a wasteful number, since it uses less digits than its factorization.

72991575 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1288 (or 1280 counting only the distinct ones).

The product of its digits is 198450, while the sum is 45.

The square root of 72991575 is about 8543.5106952587. The cubic root of 72991575 is about 417.9178409681.

The spelling of 72991575 in words is "seventy-two million, nine hundred ninety-one thousand, five hundred seventy-five".