491239951 has 2 divisors, whose sum is σ = 491239952. Its totient is φ = 491239950.

The previous prime is 491239949. The next prime is 491239979. The reversal of 491239951 is 159932194.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 491239951 - 2¹ = 491239949 is a prime.

It is a super-3 number, since 3×491239951³ (a number of 27 digits) contains 333 as substring.

Together with 491239949, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 491239898 and 491239907.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (491269951) 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, 245619975 + 245619976.

It is an arithmetic number, because the mean of its divisors is an integer number (245619976).

Almost surely, 2^491239951 is an apocalyptic number.

491239951 is a deficient number, since it is larger than the sum of its proper divisors (1).

491239951 is an equidigital number, since it uses as much as digits as its factorization.

491239951 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 87480, while the sum is 43.

The square root of 491239951 is about 22163.9335633366. The cubic root of 491239951 is about 789.0379524496.

The spelling of 491239951 in words is "four hundred ninety-one million, two hundred thirty-nine thousand, nine hundred fifty-one".