72657281 has 2 divisors, whose sum is σ = 72657282. Its totient is φ = 72657280.

The previous prime is 72657271. The next prime is 72657301. The reversal of 72657281 is 18275627.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 38551681 + 34105600 = 6209^2 + 5840^2 .

It is a cyclic number.

It is not a de Polignac number, because 72657281 - 2¹⁰ = 72656257 is a prime.

It is a super-2 number, since 2×72657281² = 10558160964625922, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (72657271) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36328640 + 36328641.

It is an arithmetic number, because the mean of its divisors is an integer number (36328641).

Almost surely, 2^72657281 is an apocalyptic number.

It is an amenable number.

72657281 is a deficient number, since it is larger than the sum of its proper divisors (1).

72657281 is an equidigital number, since it uses as much as digits as its factorization.

72657281 is an evil number, because the sum of its binary digits is even.

The product of its digits is 47040, while the sum is 38.

The square root of 72657281 is about 8523.9240376719. The cubic root of 72657281 is about 417.2788573913.

The spelling of 72657281 in words is "seventy-two million, six hundred fifty-seven thousand, two hundred eighty-one".