99811840 has 80 divisors (see below), whose sum is σ = 241984512. Its totient is φ = 39481344.

The previous prime is 99811819. The next prime is 99811849. The reversal of 99811840 is 4811899.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (40).

It is a junction number, because it is equal to n+sod(n) for n = 99811793 and 99811802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99811849) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 324967 + ... + 325273.

Almost surely, 2^99811840 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 99811840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (120992256).

99811840 is an abundant number, since it is smaller than the sum of its proper divisors (142172672).

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

99811840 is a wasteful number, since it uses less digits than its factorization.

99811840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 457 (or 441 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 40.

The square root of 99811840 is about 9990.5875703084. The cubic root of 99811840 is about 463.8675801278.

The spelling of 99811840 in words is "ninety-nine million, eight hundred eleven thousand, eight hundred forty".