991642624 has 88 divisors (see below), whose sum is σ = 2327357120. Its totient is φ = 413392896.

The previous prime is 991642607. The next prime is 991642649. The reversal of 991642624 is 426246199.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 263347 + ... + 267085.

It is an arithmetic number, because the mean of its divisors is an integer number (26447240).

Almost surely, 2^991642624 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 991642624, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1163678560).

991642624 is an abundant number, since it is smaller than the sum of its proper divisors (1335714496).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

991642624 is a wasteful number, since it uses less digits than its factorization.

991642624 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3803 (or 3785 counting only the distinct ones).

The product of its digits is 186624, while the sum is 43.

The square root of 991642624 is about 31490.3576353143. The cubic root of 991642624 is about 997.2064111284.

The spelling of 991642624 in words is "nine hundred ninety-one million, six hundred forty-two thousand, six hundred twenty-four".