491172131 has 2 divisors, whose sum is σ = 491172132. Its totient is φ = 491172130.

The previous prime is 491172127. The next prime is 491172133. The reversal of 491172131 is 131271194.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 491172131 - 2² = 491172127 is a prime.

It is a super-2 number, since 2×491172131² = 482500124542162322, which contains 22 as substring.

Together with 491172133, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 491172094 and 491172103.

It is not a weakly prime, because it can be changed into another prime (491172133) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 245586065 + 245586066.

It is an arithmetic number, because the mean of its divisors is an integer number (245586066).

Almost surely, 2^491172131 is an apocalyptic number.

491172131 is a deficient number, since it is larger than the sum of its proper divisors (1).

491172131 is an equidigital number, since it uses as much as digits as its factorization.

491172131 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1512, while the sum is 29.

The square root of 491172131 is about 22162.4035474495. The cubic root of 491172131 is about 789.0016395664.

The spelling of 491172131 in words is "four hundred ninety-one million, one hundred seventy-two thousand, one hundred thirty-one".