172421999 has 2 divisors, whose sum is σ = 172422000. Its totient is φ = 172421998.

The previous prime is 172421983. The next prime is 172422001. The reversal of 172421999 is 999124271.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 172421999 - 2⁴ = 172421983 is a prime.

It is a Sophie Germain prime.

Together with 172422001, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (172427999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86210999 + 86211000.

It is an arithmetic number, because the mean of its divisors is an integer number (86211000).

Almost surely, 2^172421999 is an apocalyptic number.

172421999 is a deficient number, since it is larger than the sum of its proper divisors (1).

172421999 is an equidigital number, since it uses as much as digits as its factorization.

172421999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 81648, while the sum is 44.

The square root of 172421999 is about 13130.9557534857. The cubic root of 172421999 is about 556.5842234311.

The spelling of 172421999 in words is "one hundred seventy-two million, four hundred twenty-one thousand, nine hundred ninety-nine".