99999640 has 32 divisors (see below), whose sum is σ = 242308080. Its totient is φ = 36922752.

The previous prime is 99999623. The next prime is 99999643. The reversal of 99999640 is 4699999.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99999643) 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, 95634 + ... + 96673.

Almost surely, 2^99999640 is an apocalyptic number.

It is an amenable number.

99999640 is an abundant number, since it is smaller than the sum of its proper divisors (142308440).

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

99999640 is a wasteful number, since it uses less digits than its factorization.

99999640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 192331 (or 192327 counting only the distinct ones).

The product of its (nonzero) digits is 1417176, while the sum is 55.

The square root of 99999640 is about 9999.9819999838. The cubic root of 99999640 is about 464.1583263699.

The spelling of 99999640 in words is "ninety-nine million, nine hundred ninety-nine thousand, six hundred forty".