491621969 has 2 divisors, whose sum is σ = 491621970. Its totient is φ = 491621968.

The previous prime is 491621957. The next prime is 491621983. The reversal of 491621969 is 969126194.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 480486400 + 11135569 = 21920^2 + 3337^2 .

It is a cyclic number.

It is not a de Polignac number, because 491621969 - 2¹² = 491617873 is a prime.

It is a super-2 number, since 2×491621969² = 483384320806873922, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (491621069) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 245810984 + 245810985.

It is an arithmetic number, because the mean of its divisors is an integer number (245810985).

Almost surely, 2^491621969 is an apocalyptic number.

It is an amenable number.

491621969 is a deficient number, since it is larger than the sum of its proper divisors (1).

491621969 is an equidigital number, since it uses as much as digits as its factorization.

491621969 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 209952, while the sum is 47.

The square root of 491621969 is about 22172.5498984668. The cubic root of 491621969 is about 789.2424340529.

The spelling of 491621969 in words is "four hundred ninety-one million, six hundred twenty-one thousand, nine hundred sixty-nine".