991229580 has 216 divisors, whose sum is σ = 3356694432. Its totient is φ = 236544000.

The previous prime is 991229567. The next prime is 991229609. The reversal of 991229580 is 85922199.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 1546060 + ... + 1546700.

It is an arithmetic number, because the mean of its divisors is an integer number (15540252).

Almost surely, 2^991229580 is an apocalyptic number.

991229580 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 991229580, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1678347216).

991229580 is an abundant number, since it is smaller than the sum of its proper divisors (2365464852).

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

991229580 is a wasteful number, since it uses less digits than its factorization.

991229580 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 749 (or 733 counting only the distinct ones).

The product of its (nonzero) digits is 116640, while the sum is 45.

The square root of 991229580 is about 31483.7986907552. The cubic root of 991229580 is about 997.0679380819.

The spelling of 991229580 in words is "nine hundred ninety-one million, two hundred twenty-nine thousand, five hundred eighty".