172390221 has 16 divisors (see below), whose sum is σ = 266497920. Its totient is φ = 109929600.

The previous prime is 172390213. The next prime is 172390223. The reversal of 172390221 is 122093271.

It is not a de Polignac number, because 172390221 - 2³ = 172390213 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (172390223) 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, 138180 + ... + 139421.

It is an arithmetic number, because the mean of its divisors is an integer number (16656120).

Almost surely, 2^172390221 is an apocalyptic number.

It is an amenable number.

172390221 is a deficient number, since it is larger than the sum of its proper divisors (94107699).

172390221 is a wasteful number, since it uses less digits than its factorization.

172390221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 277633 (or 277627 counting only the distinct ones).

The product of its (nonzero) digits is 1512, while the sum is 27.

The square root of 172390221 is about 13129.7456563332. The cubic root of 172390221 is about 556.5500278330.

The spelling of 172390221 in words is "one hundred seventy-two million, three hundred ninety thousand, two hundred twenty-one".