491239979 has 2 divisors, whose sum is σ = 491239980. Its totient is φ = 491239978.

The previous prime is 491239951. The next prime is 491240021. The reversal of 491239979 is 979932194.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-491239979 is a prime.

It is a super-3 number, since 3×491239979³ (a number of 27 digits) contains 333 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 491239979.

It is not a weakly prime, because it can be changed into another prime (491239909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 245619989 + 245619990.

It is an arithmetic number, because the mean of its divisors is an integer number (245619990).

Almost surely, 2^491239979 is an apocalyptic number.

491239979 is a deficient number, since it is larger than the sum of its proper divisors (1).

491239979 is an equidigital number, since it uses as much as digits as its factorization.

491239979 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1102248, while the sum is 53.

The square root of 491239979 is about 22163.9341949935. The cubic root of 491239979 is about 789.0379674409.

The spelling of 491239979 in words is "four hundred ninety-one million, two hundred thirty-nine thousand, nine hundred seventy-nine".