72436581 has 36 divisors (see below), whose sum is σ = 122296096. Its totient is φ = 40463280.

The previous prime is 72436571. The next prime is 72436583. The reversal of 72436581 is 18563427.

72436581 is a `hidden beast` number, since 72 + 4 + 3 + 6 + 581 = 666.

It is not a de Polignac number, because 72436581 - 2⁵ = 72436549 is a prime.

It is a super-2 number, since 2×72436581² = 10494116533939122, which contains 22 as substring.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72436583) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 552886 + ... + 553016.

Almost surely, 2^72436581 is an apocalyptic number.

It is an amenable number.

72436581 is a deficient number, since it is larger than the sum of its proper divisors (49859515).

72436581 is a wasteful number, since it uses less digits than its factorization.

72436581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 342 (or 208 counting only the distinct ones).

The product of its digits is 40320, while the sum is 36.

The square root of 72436581 is about 8510.9682762891. The cubic root of 72436581 is about 416.8559273177.

It can be divided in two parts, 7243 and 6581, that added together give a cube (13824 = 24³).

The spelling of 72436581 in words is "seventy-two million, four hundred thirty-six thousand, five hundred eighty-one".