72687257 has 6 divisors (see below), whose sum is σ = 77214798. Its totient is φ = 68411264.

The previous prime is 72687227. The next prime is 72687271. The reversal of 72687257 is 75278627.

It is a happy number.

It can be written as a sum of positive squares in 3 ways, for example, as 44342281 + 28344976 = 6659^2 + 5324^2 .

It is a de Polignac number, because none of the positive numbers 2^k-72687257 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72687227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 125468 + ... + 126045.

It is an arithmetic number, because the mean of its divisors is an integer number (12869133).

Almost surely, 2^72687257 is an apocalyptic number.

It is an amenable number.

72687257 is a deficient number, since it is larger than the sum of its proper divisors (4527541).

72687257 is a wasteful number, since it uses less digits than its factorization.

72687257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 251547 (or 251530 counting only the distinct ones).

The product of its digits is 329280, while the sum is 44.

The square root of 72687257 is about 8525.6822014429. The cubic root of 72687257 is about 417.3362346703.

The spelling of 72687257 in words is "seventy-two million, six hundred eighty-seven thousand, two hundred fifty-seven".