172921087 has 2 divisors, whose sum is σ = 172921088. Its totient is φ = 172921086.

The previous prime is 172921081. The next prime is 172921097. The reversal of 172921087 is 780129271.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 172921087 - 2⁷ = 172920959 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (172921081) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86460543 + 86460544.

It is an arithmetic number, because the mean of its divisors is an integer number (86460544).

Almost surely, 2^172921087 is an apocalyptic number.

172921087 is a deficient number, since it is larger than the sum of its proper divisors (1).

172921087 is an equidigital number, since it uses as much as digits as its factorization.

172921087 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 14112, while the sum is 37.

The square root of 172921087 is about 13149.9462736545. The cubic root of 172921087 is about 557.1207305981.

The spelling of 172921087 in words is "one hundred seventy-two million, nine hundred twenty-one thousand, eighty-seven".