172505021 has 16 divisors (see below), whose sum is σ = 193052160. Its totient is φ = 153048000.

The previous prime is 172505017. The next prime is 172505027. The reversal of 172505021 is 120505271.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 172505021 - 2² = 172505017 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (172505027) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 93716 + ... + 95538.

It is an arithmetic number, because the mean of its divisors is an integer number (12065760).

Almost surely, 2^172505021 is an apocalyptic number.

It is an amenable number.

172505021 is a deficient number, since it is larger than the sum of its proper divisors (20547139).

172505021 is a wasteful number, since it uses less digits than its factorization.

172505021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2116.

The product of its (nonzero) digits is 700, while the sum is 23.

The square root of 172505021 is about 13134.1166813760. The cubic root of 172505021 is about 556.6735417336.

The spelling of 172505021 in words is "one hundred seventy-two million, five hundred five thousand, twenty-one".