172291979 has 2 divisors, whose sum is σ = 172291980. Its totient is φ = 172291978.

The previous prime is 172291967. The next prime is 172291997. The reversal of 172291979 is 979192271.

Together with next prime (172291997) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 172291979 - 2⁸ = 172291723 is a prime.

It is not a weakly prime, because it can be changed into another prime (172291939) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86145989 + 86145990.

It is an arithmetic number, because the mean of its divisors is an integer number (86145990).

Almost surely, 2^172291979 is an apocalyptic number.

172291979 is a deficient number, since it is larger than the sum of its proper divisors (1).

172291979 is an equidigital number, since it uses as much as digits as its factorization.

172291979 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 142884, while the sum is 47.

The square root of 172291979 is about 13126.0039235100. The cubic root of 172291979 is about 556.4442852195. Note that the first 3 decimals are identical.

The spelling of 172291979 in words is "one hundred seventy-two million, two hundred ninety-one thousand, nine hundred seventy-nine".