99988821 has 12 divisors (see below), whose sum is σ = 146796780. Its totient is φ = 65566080.

The previous prime is 99988813. The next prime is 99988829. The reversal of 99988821 is 12888999.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (99988813) and next prime (99988829).

It can be written as a sum of positive squares in 2 ways, for example, as 14333796 + 85655025 = 3786^2 + 9255^2 .

It is not a de Polignac number, because 99988821 - 2³ = 99988813 is a prime.

It is a Curzon number.

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 (99988829) 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 11 ways as a sum of consecutive naturals, for example, 90516 + ... + 91613.

It is an arithmetic number, because the mean of its divisors is an integer number (12233065).

Almost surely, 2^99988821 is an apocalyptic number.

It is an amenable number.

99988821 is a deficient number, since it is larger than the sum of its proper divisors (46807959).

99988821 is a wasteful number, since it uses less digits than its factorization.

99988821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 182196 (or 182193 counting only the distinct ones).

The product of its digits is 746496, while the sum is 54.

The square root of 99988821 is about 9999.4410343779. The cubic root of 99988821 is about 464.1415866095.

The spelling of 99988821 in words is "ninety-nine million, nine hundred eighty-eight thousand, eight hundred twenty-one".