99721125 has 144 divisors (see below), whose sum is σ = 220094784. Its totient is φ = 44906400.

The previous prime is 99721121. The next prime is 99721159. The reversal of 99721125 is 52112799.

It is not a de Polignac number, because 99721125 - 2² = 99721121 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 99721125.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99721121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 1488342 + ... + 1488408.

It is an arithmetic number, because the mean of its divisors is an integer number (1528436).

Almost surely, 2^99721125 is an apocalyptic number.

It is an amenable number.

99721125 is an abundant number, since it is smaller than the sum of its proper divisors (120373659).

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

99721125 is an equidigital number, since it uses as much as digits as its factorization.

99721125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111 (or 82 counting only the distinct ones).

The product of its digits is 11340, while the sum is 36.

The square root of 99721125 is about 9986.0465150128. The cubic root of 99721125 is about 463.7270072853.

It can be divided in two parts, 997 and 21125, that added together give a palindrome (22122).

The spelling of 99721125 in words is "ninety-nine million, seven hundred twenty-one thousand, one hundred twenty-five".