99639840 has 192 divisors, whose sum is σ = 330728832. Its totient is φ = 25190400.

The previous prime is 99639823. The next prime is 99639847. The reversal of 99639840 is 4893699.

It is a happy number.

It is a super-3 number, since 3×99639840³ (a number of 25 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 99639840.

It is not an unprimeable number, because it can be changed into a prime (99639847) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1200439 + ... + 1200521.

It is an arithmetic number, because the mean of its divisors is an integer number (1722546).

Almost surely, 2^99639840 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 99639840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (165364416).

99639840 is an abundant number, since it is smaller than the sum of its proper divisors (231088992).

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

99639840 is a wasteful number, since it uses less digits than its factorization.

99639840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 203 (or 195 counting only the distinct ones).

The product of its (nonzero) digits is 419904, while the sum is 48.

The square root of 99639840 is about 9981.9757563320. The cubic root of 99639840 is about 463.6009748250.

The spelling of 99639840 in words is "ninety-nine million, six hundred thirty-nine thousand, eight hundred forty".