72907081 has 4 divisors (see below), whose sum is σ = 78515332. Its totient is φ = 67298832.

The previous prime is 72907063. The next prime is 72907091. The reversal of 72907081 is 18070927.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18070927 = 7 ⋅2581561.

It can be written as a sum of positive squares in 2 ways, for example, as 5929225 + 66977856 = 2435^2 + 8184^2 .

It is a cyclic number.

It is not a de Polignac number, because 72907081 - 2⁵ = 72907049 is a prime.

It is a super-2 number, since 2×72907081² = 10630884919881122, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72907001) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2804106 + ... + 2804131.

It is an arithmetic number, because the mean of its divisors is an integer number (19628833).

Almost surely, 2^72907081 is an apocalyptic number.

It is an amenable number.

72907081 is a deficient number, since it is larger than the sum of its proper divisors (5608251).

72907081 is a wasteful number, since it uses less digits than its factorization.

72907081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5608250.

The product of its (nonzero) digits is 7056, while the sum is 34.

The square root of 72907081 is about 8538.5643406840. The cubic root of 72907081 is about 417.7565201389.

The spelling of 72907081 in words is "seventy-two million, nine hundred seven thousand, eighty-one".