491172139 has 2 divisors, whose sum is σ = 491172140. Its totient is φ = 491172138.

The previous prime is 491172133. The next prime is 491172193. The reversal of 491172139 is 931271194.

Together with next prime (491172193) 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 491172139 - 2³ = 491172131 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 491172098 and 491172107.

It is not a weakly prime, because it can be changed into another prime (491172131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 245586069 + 245586070.

It is an arithmetic number, because the mean of its divisors is an integer number (245586070).

Almost surely, 2^491172139 is an apocalyptic number.

491172139 is a deficient number, since it is larger than the sum of its proper divisors (1).

491172139 is an equidigital number, since it uses as much as digits as its factorization.

491172139 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 13608, while the sum is 37.

The square root of 491172139 is about 22162.4037279353. The cubic root of 491172139 is about 789.0016438501.

The spelling of 491172139 in words is "four hundred ninety-one million, one hundred seventy-two thousand, one hundred thirty-nine".