172865531 has 2 divisors, whose sum is σ = 172865532. Its totient is φ = 172865530.

The previous prime is 172865519. The next prime is 172865557. The reversal of 172865531 is 135568271.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 172865531 - 2⁶ = 172865467 is a prime.

It is a super-2 number, since 2×172865531² = 59764983615823922, which contains 22 as substring.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (172865431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86432765 + 86432766.

It is an arithmetic number, because the mean of its divisors is an integer number (86432766).

Almost surely, 2^172865531 is an apocalyptic number.

172865531 is a deficient number, since it is larger than the sum of its proper divisors (1).

172865531 is an equidigital number, since it uses as much as digits as its factorization.

172865531 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 50400, while the sum is 38.

The square root of 172865531 is about 13147.8336998914. The cubic root of 172865531 is about 557.0610603845.

The spelling of 172865531 in words is "one hundred seventy-two million, eight hundred sixty-five thousand, five hundred thirty-one".