991303820 has 24 divisors (see below), whose sum is σ = 2241872304. Its totient is φ = 366019776.

The previous prime is 991303801. The next prime is 991303867. The reversal of 991303820 is 28303199.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1906094 + ... + 1906613.

It is an arithmetic number, because the mean of its divisors is an integer number (93411346).

Almost surely, 2^991303820 is an apocalyptic number.

It is an amenable number.

991303820 is an abundant number, since it is smaller than the sum of its proper divisors (1250568484).

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

991303820 is a wasteful number, since it uses less digits than its factorization.

991303820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3812729 (or 3812727 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 35.

The square root of 991303820 is about 31484.9776877799. The cubic root of 991303820 is about 997.0928298854.

The spelling of 991303820 in words is "nine hundred ninety-one million, three hundred three thousand, eight hundred twenty".