99640840 has 64 divisors (see below), whose sum is σ = 244263600. Its totient is φ = 36360192.

The previous prime is 99640831. The next prime is 99640873. The reversal of 99640840 is 4804699.

It can be written as a sum of positive squares in 8 ways, for example, as 956484 + 98684356 = 978^2 + 9934^2 .

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 = 99640793 and 99640802.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 45204 + ... + 47356.

Almost surely, 2^99640840 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 99640840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (122131800).

99640840 is an abundant number, since it is smaller than the sum of its proper divisors (144622760).

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

99640840 is a wasteful number, since it uses less digits than its factorization.

99640840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2266 (or 2262 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 40.

The square root of 99640840 is about 9982.0258464903. The cubic root of 99640840 is about 463.6025257422.

The spelling of 99640840 in words is "ninety-nine million, six hundred forty thousand, eight hundred forty".