72511309 has 12 divisors (see below), whose sum is σ = 79233876. Its totient is φ = 66323712.

The previous prime is 72511259. The next prime is 72511331. The reversal of 72511309 is 90311527.

It can be written as a sum of positive squares in 6 ways, for example, as 54686025 + 17825284 = 7395^2 + 4222^2 .

It is not a de Polignac number, because 72511309 - 2¹⁵ = 72478541 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72511399) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 17199 + ... + 20995.

It is an arithmetic number, because the mean of its divisors is an integer number (6602823).

Almost surely, 2^72511309 is an apocalyptic number.

It is an amenable number.

72511309 is a deficient number, since it is larger than the sum of its proper divisors (6722567).

72511309 is a wasteful number, since it uses less digits than its factorization.

72511309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3936 (or 3923 counting only the distinct ones).

The product of its (nonzero) digits is 1890, while the sum is 28.

The square root of 72511309 is about 8515.3572444144. The cubic root of 72511309 is about 416.9992255582. Note that the first 3 decimals are identical.

The spelling of 72511309 in words is "seventy-two million, five hundred eleven thousand, three hundred nine".