991967620 has 96 divisors (see below), whose sum is σ = 2474841600. Its totient is φ = 326774784.

The previous prime is 991967617. The next prime is 991967659. The reversal of 991967620 is 26769199.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1067316 + ... + 1068244.

It is an arithmetic number, because the mean of its divisors is an integer number (25779600).

Almost surely, 2^991967620 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 991967620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1237420800).

991967620 is an abundant number, since it is smaller than the sum of its proper divisors (1482873980).

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

991967620 is a wasteful number, since it uses less digits than its factorization.

991967620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1237 (or 1235 counting only the distinct ones).

The product of its (nonzero) digits is 367416, while the sum is 49.

The square root of 991967620 is about 31495.5174588385. The cubic root of 991967620 is about 997.3153390454.

The spelling of 991967620 in words is "nine hundred ninety-one million, nine hundred sixty-seven thousand, six hundred twenty".