72166565 has 4 divisors (see below), whose sum is σ = 86599884. Its totient is φ = 57733248.

The previous prime is 72166561. The next prime is 72166583. The reversal of 72166565 is 56566127.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 56566127 = 269 ⋅210283.

It can be written as a sum of positive squares in 2 ways, for example, as 39150049 + 33016516 = 6257^2 + 5746^2 .

It is a cyclic number.

It is not a de Polignac number, because 72166565 - 2² = 72166561 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 (72166561) 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, 7216652 + ... + 7216661.

It is an arithmetic number, because the mean of its divisors is an integer number (21649971).

Almost surely, 2^72166565 is an apocalyptic number.

It is an amenable number.

72166565 is a deficient number, since it is larger than the sum of its proper divisors (14433319).

72166565 is a wasteful number, since it uses less digits than its factorization.

72166565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14433318.

The product of its digits is 75600, while the sum is 38.

The square root of 72166565 is about 8495.0906410703. The cubic root of 72166565 is about 416.3373223239.

The spelling of 72166565 in words is "seventy-two million, one hundred sixty-six thousand, five hundred sixty-five".