991887936 has 112 divisors (see below), whose sum is σ = 2836151808. Its totient is φ = 304128000.

The previous prime is 991887893. The next prime is 991887943. The reversal of 991887936 is 639788199.

It is a self number, because there is not a number n which added to its sum of digits gives 991887936.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1000401 + ... + 1001391.

It is an arithmetic number, because the mean of its divisors is an integer number (25322784).

Almost surely, 2^991887936 is an apocalyptic number.

991887936 is a gapful number since it is divisible by the number (96) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 991887936, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1418075904).

991887936 is an abundant number, since it is smaller than the sum of its proper divisors (1844263872).

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

991887936 is a wasteful number, since it uses less digits than its factorization.

991887936 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1420 (or 1410 counting only the distinct ones).

The product of its digits is 5878656, while the sum is 60.

The square root of 991887936 is about 31494.2524280225. The cubic root of 991887936 is about 997.2886338042.

The spelling of 991887936 in words is "nine hundred ninety-one million, eight hundred eighty-seven thousand, nine hundred thirty-six".