72275561 has 6 divisors (see below), whose sum is σ = 73997370. Its totient is φ = 70592928.

The previous prime is 72275537. The next prime is 72275587. The reversal of 72275561 is 16557227.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 56625625 + 15649936 = 7525^2 + 3956^2 .

It is a de Polignac number, because none of the positive numbers 2^k-72275561 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (72275261) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 17696 + ... + 21393.

It is an arithmetic number, because the mean of its divisors is an integer number (12332895).

Almost surely, 2^72275561 is an apocalyptic number.

It is an amenable number.

72275561 is a deficient number, since it is larger than the sum of its proper divisors (1721809).

72275561 is an equidigital number, since it uses as much as digits as its factorization.

72275561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39175 (or 39132 counting only the distinct ones).

The product of its digits is 29400, while the sum is 35.

The square root of 72275561 is about 8501.5034552719. The cubic root of 72275561 is about 416.5468204296.

The spelling of 72275561 in words is "seventy-two million, two hundred seventy-five thousand, five hundred sixty-one".