99657840 has 80 divisors (see below), whose sum is σ = 309899808. Its totient is φ = 26492928.

The previous prime is 99657821. The next prime is 99657841. The reversal of 99657840 is 4875699.

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 (48).

It is a self number, because there is not a number n which added to its sum of digits gives 99657840.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99657841) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 147744 + ... + 148416.

Almost surely, 2^99657840 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 99657840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (154949904).

99657840 is an abundant number, since it is smaller than the sum of its proper divisors (210241968).

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

99657840 is a wasteful number, since it uses less digits than its factorization.

99657840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1306 (or 1300 counting only the distinct ones).

The product of its (nonzero) digits is 544320, while the sum is 48.

The square root of 99657840 is about 9982.8773407270. The cubic root of 99657840 is about 463.6288897471.

The spelling of 99657840 in words is "ninety-nine million, six hundred fifty-seven thousand, eight hundred forty".