491999351 has 2 divisors, whose sum is σ = 491999352. Its totient is φ = 491999350.

The previous prime is 491999327. The next prime is 491999353. The reversal of 491999351 is 153999194.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-491999351 is a prime.

It is a super-2 number, since 2×491999351² = 484126722768842402, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 491999353, it forms a pair of twin primes.

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 491999351.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (491999353) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 245999675 + 245999676.

It is an arithmetic number, because the mean of its divisors is an integer number (245999676).

Almost surely, 2^491999351 is an apocalyptic number.

491999351 is a deficient number, since it is larger than the sum of its proper divisors (1).

491999351 is an equidigital number, since it uses as much as digits as its factorization.

491999351 is an evil number, because the sum of its binary digits is even.

The product of its digits is 393660, while the sum is 50.

The square root of 491999351 is about 22181.0583832242. The cubic root of 491999351 is about 789.4443301763. Note that the first 3 decimals are identical.

The spelling of 491999351 in words is "four hundred ninety-one million, nine hundred ninety-nine thousand, three hundred fifty-one".