172921091 has 8 divisors (see below), whose sum is σ = 202965600. Its totient is φ = 144211968.

The previous prime is 172921087. The next prime is 172921097. The reversal of 172921091 is 190129271.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 172921091 - 2² = 172921087 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (172921097) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 333566 + ... + 334083.

It is an arithmetic number, because the mean of its divisors is an integer number (25370700).

Almost surely, 2^172921091 is an apocalyptic number.

172921091 is a deficient number, since it is larger than the sum of its proper divisors (30044509).

172921091 is an equidigital number, since it uses as much as digits as its factorization.

172921091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 667693.

The product of its (nonzero) digits is 2268, while the sum is 32.

The square root of 172921091 is about 13149.9464257464. The cubic root of 172921091 is about 557.1207348938.

The spelling of 172921091 in words is "one hundred seventy-two million, nine hundred twenty-one thousand, ninety-one".