172424921 has 4 divisors (see below), whose sum is σ = 177085092. Its totient is φ = 167764752.

The previous prime is 172424911. The next prime is 172424927. The reversal of 172424921 is 129424271.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 149719696 + 22705225 = 12236^2 + 4765^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-172424921 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (172424927) 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 in 3 ways as a sum of consecutive naturals, for example, 2330030 + ... + 2330103.

It is an arithmetic number, because the mean of its divisors is an integer number (44271273).

Almost surely, 2^172424921 is an apocalyptic number.

It is an amenable number.

172424921 is a deficient number, since it is larger than the sum of its proper divisors (4660171).

172424921 is an equidigital number, since it uses as much as digits as its factorization.

172424921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4660170.

The product of its digits is 8064, while the sum is 32.

The square root of 172424921 is about 13131.0670168117. The cubic root of 172424921 is about 556.5873675193.

The spelling of 172424921 in words is "one hundred seventy-two million, four hundred twenty-four thousand, nine hundred twenty-one".