172161257 has 4 divisors (see below), whose sum is σ = 174730896. Its totient is φ = 169591620.

The previous prime is 172161247. The next prime is 172161271. The reversal of 172161257 is 752161271.

172161257 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 752161271 = 37 ⋅20328683.

It is a cyclic number.

It is not a de Polignac number, because 172161257 - 2²⁰ = 171112681 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (172161217) 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, 1284719 + ... + 1284852.

It is an arithmetic number, because the mean of its divisors is an integer number (43682724).

Almost surely, 2^172161257 is an apocalyptic number.

It is an amenable number.

172161257 is a deficient number, since it is larger than the sum of its proper divisors (2569639).

172161257 is an equidigital number, since it uses as much as digits as its factorization.

172161257 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2569638.

The product of its digits is 5880, while the sum is 32.

The square root of 172161257 is about 13121.0234737996. The cubic root of 172161257 is about 556.3035204657.

The spelling of 172161257 in words is "one hundred seventy-two million, one hundred sixty-one thousand, two hundred fifty-seven".