991431461 has 2 divisors, whose sum is σ = 991431462. Its totient is φ = 991431460.

The previous prime is 991431451. The next prime is 991431479. The reversal of 991431461 is 164134199.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 686754436 + 304677025 = 26206^2 + 17455^2 .

It is a cyclic number.

It is not a de Polignac number, because 991431461 - 2²² = 987237157 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (991431451) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495715730 + 495715731.

It is an arithmetic number, because the mean of its divisors is an integer number (495715731).

Almost surely, 2^991431461 is an apocalyptic number.

It is an amenable number.

991431461 is a deficient number, since it is larger than the sum of its proper divisors (1).

991431461 is an equidigital number, since it uses as much as digits as its factorization.

991431461 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 23328, while the sum is 38.

The square root of 991431461 is about 31487.0046368339. The cubic root of 991431461 is about 997.1356235144.

The spelling of 991431461 in words is "nine hundred ninety-one million, four hundred thirty-one thousand, four hundred sixty-one".