999155520 has 224 divisors, whose sum is σ = 3845600640. Its totient is φ = 242196480.

The previous prime is 999155519. The next prime is 999155543. The reversal of 999155520 is 25551999.

999155520 is a `hidden beast` number, since 9 + 9 + 91 + 5 + 552 + 0 = 666.

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

It is a congruent number.

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, 89784 + ... + 100296.

It is an arithmetic number, because the mean of its divisors is an integer number (17167860).

Almost surely, 2^999155520 is an apocalyptic number.

999155520 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 999155520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1922800320).

999155520 is an abundant number, since it is smaller than the sum of its proper divisors (2846445120).

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

999155520 is a wasteful number, since it uses less digits than its factorization.

999155520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10550 (or 10534 counting only the distinct ones).

The product of its (nonzero) digits is 182250, while the sum is 45.

The square root of 999155520 is about 31609.4213803417. The cubic root of 999155520 is about 999.7184273910.

The spelling of 999155520 in words is "nine hundred ninety-nine million, one hundred fifty-five thousand, five hundred twenty".