172220857 has 4 divisors (see below), whose sum is σ = 173926116. Its totient is φ = 170515600.

The previous prime is 172220837. The next prime is 172220911. The reversal of 172220857 is 758022271.

172220857 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.

It can be written as a sum of positive squares in 2 ways, for example, as 135932281 + 36288576 = 11659^2 + 6024^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-172220857 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (172220837) 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, 852478 + ... + 852679.

It is an arithmetic number, because the mean of its divisors is an integer number (43481529).

Almost surely, 2^172220857 is an apocalyptic number.

It is an amenable number.

172220857 is a deficient number, since it is larger than the sum of its proper divisors (1705259).

172220857 is a wasteful number, since it uses less digits than its factorization.

172220857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1705258.

The product of its (nonzero) digits is 15680, while the sum is 34.

The square root of 172220857 is about 13123.2944415646. The cubic root of 172220857 is about 556.3677080867.

The spelling of 172220857 in words is "one hundred seventy-two million, two hundred twenty thousand, eight hundred fifty-seven".