72172657 has 2 divisors, whose sum is σ = 72172658. Its totient is φ = 72172656.

The previous prime is 72172649. The next prime is 72172663. The reversal of 72172657 is 75627127.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 50680161 + 21492496 = 7119^2 + 4636^2 .

It is a cyclic number.

It is not a de Polignac number, because 72172657 - 2³ = 72172649 is a prime.

It is not a weakly prime, because it can be changed into another prime (72172757) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36086328 + 36086329.

It is an arithmetic number, because the mean of its divisors is an integer number (36086329).

Almost surely, 2^72172657 is an apocalyptic number.

It is an amenable number.

72172657 is a deficient number, since it is larger than the sum of its proper divisors (1).

72172657 is an equidigital number, since it uses as much as digits as its factorization.

72172657 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 41160, while the sum is 37.

The square root of 72172657 is about 8495.4491935389. The cubic root of 72172657 is about 416.3490371469.

The spelling of 72172657 in words is "seventy-two million, one hundred seventy-two thousand, six hundred fifty-seven".