72172845 has 24 divisors (see below), whose sum is σ = 125804952. Its totient is φ = 38275200.

The previous prime is 72172823. The next prime is 72172847. The reversal of 72172845 is 54827127.

It can be written as a sum of positive squares in 4 ways, for example, as 7193124 + 64979721 = 2682^2 + 8061^2 .

It is not a de Polignac number, because 72172845 - 2⁵ = 72172813 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72172847) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 3715 + ... + 12575.

It is an arithmetic number, because the mean of its divisors is an integer number (5241873).

Almost surely, 2^72172845 is an apocalyptic number.

It is an amenable number.

72172845 is a deficient number, since it is larger than the sum of its proper divisors (53632107).

72172845 is a wasteful number, since it uses less digits than its factorization.

72172845 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9053 (or 9050 counting only the distinct ones).

The product of its digits is 31360, while the sum is 36.

The square root of 72172845 is about 8495.4602582791. The cubic root of 72172845 is about 416.3493986575.

The spelling of 72172845 in words is "seventy-two million, one hundred seventy-two thousand, eight hundred forty-five".