991953280 has 64 divisors (see below), whose sum is σ = 2385845280. Its totient is φ = 394362880.

The previous prime is 991953271. The next prime is 991953307. The reversal of 991953280 is 82359199.

It is a tau number, because it is divible by the number of its divisors (64).

It is a self number, because there is not a number n which added to its sum of digits gives 991953280.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 102240 + ... + 111520.

Almost surely, 2^991953280 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 991953280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1192922640).

991953280 is an abundant number, since it is smaller than the sum of its proper divisors (1393892000).

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

991953280 is a wasteful number, since it uses less digits than its factorization.

991953280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9467 (or 9455 counting only the distinct ones).

The product of its (nonzero) digits is 174960, while the sum is 46.

The square root of 991953280 is about 31495.2898065727. The cubic root of 991953280 is about 997.3105332531.

It can be divided in two parts, 991 and 953280, that added together give a triangular number (954271 = T₁₃₈₁).

The spelling of 991953280 in words is "nine hundred ninety-one million, nine hundred fifty-three thousand, two hundred eighty".