99999999720 has 192 divisors, whose sum is σ = 342309240000. Its totient is φ = 25248098304.

The previous prime is 99999999713. The next prime is 99999999731. The reversal of 99999999720 is 2799999999.

It is a nialpdrome in base 10.

It is a self number, because there is not a number n which added to its sum of digits gives 99999999720.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 15503056 + ... + 15509504.

It is an arithmetic number, because the mean of its divisors is an integer number (1782860625).

Almost surely, 2^99999999720 is an apocalyptic number.

99999999720 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 99999999720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (171154620000).

99999999720 is an abundant number, since it is smaller than the sum of its proper divisors (242309240280).

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

99999999720 is a wasteful number, since it uses less digits than its factorization.

99999999720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8752 (or 8745 counting only the distinct ones).

The product of its (nonzero) digits is 602654094, while the sum is 81.

The spelling of 99999999720 in words is "ninety-nine billion, nine hundred ninety-nine million, nine hundred ninety-nine thousand, seven hundred twenty".