991247877 has 6 divisors (see below), whose sum is σ = 1431802502. Its totient is φ = 660831912.

The previous prime is 991247863. The next prime is 991247891. The reversal of 991247877 is 778742199.

991247877 is a `hidden beast` number, since 99 + 12 + 478 + 77 = 666.

991247877 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (991247863) and next prime (991247891).

It can be written as a sum of positive squares in only one way, i.e., 599564196 + 391683681 = 24486^2 + 19791^2 .

It is not a de Polignac number, because 991247877 - 2⁴ = 991247861 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991227877) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 55069318 + ... + 55069335.

Almost surely, 2^991247877 is an apocalyptic number.

It is an amenable number.

991247877 is a deficient number, since it is larger than the sum of its proper divisors (440554625).

991247877 is a wasteful number, since it uses less digits than its factorization.

991247877 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110138659 (or 110138656 counting only the distinct ones).

The product of its digits is 1778112, while the sum is 54.

The square root of 991247877 is about 31484.0892674379. The cubic root of 991247877 is about 997.0740729673.

The spelling of 991247877 in words is "nine hundred ninety-one million, two hundred forty-seven thousand, eight hundred seventy-seven".