99999720 has 96 divisors (see below), whose sum is σ = 326687400. Its totient is φ = 26528256.

The previous prime is 99999703. The next prime is 99999721. The reversal of 99999720 is 2799999.

It can be written as a sum of positive squares in 4 ways, for example, as 77475204 + 22524516 = 8802^2 + 4746^2 .

It is a nialpdrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (99999721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 81834 + ... + 83046.

Almost surely, 2^99999720 is an apocalyptic number.

99999720 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 99999720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (163343700).

99999720 is an abundant number, since it is smaller than the sum of its proper divisors (226687680).

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

99999720 is a wasteful number, since it uses less digits than its factorization.

99999720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1459 (or 1452 counting only the distinct ones).

The product of its (nonzero) digits is 826686, while the sum is 54.

The square root of 99999720 is about 9999.9859999902. The cubic root of 99999720 is about 464.1584501459.

The spelling of 99999720 in words is "ninety-nine million, nine hundred ninety-nine thousand, seven hundred twenty".