991253644 has 24 divisors (see below), whose sum is σ = 1796135936. Its totient is φ = 478170000.

The previous prime is 991253623. The next prime is 991253651. The reversal of 991253644 is 446352199.

It is a self number, because there is not a number n which added to its sum of digits gives 991253644.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 28969 + ... + 53119.

Almost surely, 2^991253644 is an apocalyptic number.

It is an amenable number.

991253644 is a deficient number, since it is larger than the sum of its proper divisors (804882292).

991253644 is a wasteful number, since it uses less digits than its factorization.

991253644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24517 (or 24515 counting only the distinct ones).

The product of its digits is 233280, while the sum is 43.

The square root of 991253644 is about 31484.1808532476. The cubic root of 991253644 is about 997.0760065957.

The spelling of 991253644 in words is "nine hundred ninety-one million, two hundred fifty-three thousand, six hundred forty-four".