172172421 has 24 divisors (see below), whose sum is σ = 255924864. Its totient is φ = 111481920.

The previous prime is 172172401. The next prime is 172172437. The reversal of 172172421 is 124271271.

It is a happy number.

172172421 is a `hidden beast` number, since 1 + 72 + 172 + 421 = 666.

It is not a de Polignac number, because 172172421 - 2⁷ = 172172293 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (172172401) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 56466 + ... + 59436.

It is an arithmetic number, because the mean of its divisors is an integer number (10663536).

Almost surely, 2^172172421 is an apocalyptic number.

It is an amenable number.

172172421 is a deficient number, since it is larger than the sum of its proper divisors (83752443).

172172421 is a wasteful number, since it uses less digits than its factorization.

172172421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3161 (or 3158 counting only the distinct ones).

The product of its digits is 1568, while the sum is 27.

The square root of 172172421 is about 13121.4488910333. The cubic root of 172172421 is about 556.3155449254.

The spelling of 172172421 in words is "one hundred seventy-two million, one hundred seventy-two thousand, four hundred twenty-one".