991308888 has 96 divisors (see below), whose sum is σ = 2906420400. Its totient is φ = 313020288.

The previous prime is 991308853. The next prime is 991308889. The reversal of 991308888 is 888803199.

It is a super-2 number, since 2×991308888² = 1965386622855593088, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991308889) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 71620 + ... + 84332.

Almost surely, 2^991308888 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 991308888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1453210200).

991308888 is an abundant number, since it is smaller than the sum of its proper divisors (1915111512).

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

991308888 is a wasteful number, since it uses less digits than its factorization.

991308888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12766 (or 12737 counting only the distinct ones).

The product of its (nonzero) digits is 995328, while the sum is 54.

The square root of 991308888 is about 31485.0581705037. The cubic root of 991308888 is about 997.0945290812.

The spelling of 991308888 in words is "nine hundred ninety-one million, three hundred eight thousand, eight hundred eighty-eight".