171872421 has 16 divisors (see below), whose sum is σ = 262108800. Its totient is φ = 98134848.

The previous prime is 171872413. The next prime is 171872429. The reversal of 171872421 is 124278171.

It is an interprime number because it is at equal distance from previous prime (171872413) and next prime (171872429).

It is not a de Polignac number, because 171872421 - 2³ = 171872413 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (171872429) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 33495 + ... + 38283.

It is an arithmetic number, because the mean of its divisors is an integer number (16381800).

Almost surely, 2^171872421 is an apocalyptic number.

It is an amenable number.

171872421 is a deficient number, since it is larger than the sum of its proper divisors (90236379).

171872421 is a wasteful number, since it uses less digits than its factorization.

171872421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6508.

The product of its digits is 6272, while the sum is 33.

The square root of 171872421 is about 13110.0122425572. The cubic root of 171872421 is about 555.9922417098.

The spelling of 171872421 in words is "one hundred seventy-one million, eight hundred seventy-two thousand, four hundred twenty-one".