991046944645 has 4 divisors (see below), whose sum is σ = 1189256333580. Its totient is φ = 792837555712.

The previous prime is 991046944637. The next prime is 991046944697. The reversal of 991046944645 is 546449640199.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 546449640199 = 250741 ⋅2179339.

It can be written as a sum of positive squares in 2 ways, for example, as 177179539329 + 813867405316 = 420927^2 + 902146^2 .

It is a cyclic number.

It is not a de Polignac number, because 991046944645 - 2³ = 991046944637 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 99104694460 + ... + 99104694469.

It is an arithmetic number, because the mean of its divisors is an integer number (297314083395).

Almost surely, 2^991046944645 is an apocalyptic number.

It is an amenable number.

991046944645 is a deficient number, since it is larger than the sum of its proper divisors (198209388935).

991046944645 is a wasteful number, since it uses less digits than its factorization.

991046944645 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 198209388934.

The product of its (nonzero) digits is 33592320, while the sum is 61.

The spelling of 991046944645 in words is "nine hundred ninety-one billion, forty-six million, nine hundred forty-four thousand, six hundred forty-five".