991886620 has 24 divisors (see below), whose sum is σ = 2083874688. Its totient is φ = 396580800.

The previous prime is 991886611. The next prime is 991886663. The reversal of 991886620 is 26688199.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 42250 + ... + 61390.

It is an arithmetic number, because the mean of its divisors is an integer number (86828112).

Almost surely, 2^991886620 is an apocalyptic number.

It is an amenable number.

991886620 is an abundant number, since it is smaller than the sum of its proper divisors (1091988068).

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

991886620 is a wasteful number, since it uses less digits than its factorization.

991886620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21741 (or 21739 counting only the distinct ones).

The product of its (nonzero) digits is 373248, while the sum is 49.

The square root of 991886620 is about 31494.2315353145. The cubic root of 991886620 is about 997.2881927489.

The spelling of 991886620 in words is "nine hundred ninety-one million, eight hundred eighty-six thousand, six hundred twenty".