99561728 has 54 divisors (see below), whose sum is σ = 231210126. Its totient is φ = 42663936.

The previous prime is 99561713. The next prime is 99561731. The reversal of 99561728 is 82716599.

It can be written as a sum of positive squares in only one way, i.e., 99361024 + 200704 = 9968^2 + 448^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 8576 + ... + 16512.

It is an arithmetic number, because the mean of its divisors is an integer number (4281669).

Almost surely, 2^99561728 is an apocalyptic number.

99561728 is a gapful number since it is divisible by the number (98) 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 99561728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (115605063).

99561728 is an abundant number, since it is smaller than the sum of its proper divisors (131648398).

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

99561728 is an equidigital number, since it uses as much as digits as its factorization.

99561728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7967 (or 7946 counting only the distinct ones).

The product of its digits is 272160, while the sum is 47.

The square root of 99561728 is about 9978.0623369470. The cubic root of 99561728 is about 463.4797975048.

The spelling of 99561728 in words is "ninety-nine million, five hundred sixty-one thousand, seven hundred twenty-eight".