991492457 has 4 divisors (see below), whose sum is σ = 1001309316. Its totient is φ = 981675600.

The previous prime is 991492433. The next prime is 991492459. The reversal of 991492457 is 754294199.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 754294199 = 17 ⋅44370247.

It can be written as a sum of positive squares in 2 ways, for example, as 580376281 + 411116176 = 24091^2 + 20276^2 .

It is a cyclic number.

It is not a de Polignac number, because 991492457 - 2¹⁰ = 991491433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (991492459) 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 in 3 ways as a sum of consecutive naturals, for example, 4908278 + ... + 4908479.

It is an arithmetic number, because the mean of its divisors is an integer number (250327329).

Almost surely, 2^991492457 is an apocalyptic number.

It is an amenable number.

991492457 is a deficient number, since it is larger than the sum of its proper divisors (9816859).

991492457 is a wasteful number, since it uses less digits than its factorization.

991492457 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9816858.

The product of its digits is 816480, while the sum is 50.

The square root of 991492457 is about 31487.9732120059. The cubic root of 991492457 is about 997.1560720744.

The spelling of 991492457 in words is "nine hundred ninety-one million, four hundred ninety-two thousand, four hundred fifty-seven".