99921599 has 4 divisors (see below), whose sum is σ = 101559720. Its totient is φ = 98283480.

The previous prime is 99921533. The next prime is 99921607. The reversal of 99921599 is 99512999.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 99512999 = 59 ⋅1686661.

It is a cyclic number.

It is not a de Polignac number, because 99921599 - 2²⁰ = 98873023 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 99921599.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (99921509) 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 3 ways as a sum of consecutive naturals, for example, 818969 + ... + 819090.

It is an arithmetic number, because the mean of its divisors is an integer number (25389930).

Almost surely, 2^99921599 is an apocalyptic number.

99921599 is a deficient number, since it is larger than the sum of its proper divisors (1638121).

99921599 is a wasteful number, since it uses less digits than its factorization.

99921599 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1638120.

The product of its digits is 590490, while the sum is 53.

The square root of 99921599 is about 9996.0791813591. The cubic root of 99921599 is about 464.0375499115.

The spelling of 99921599 in words is "ninety-nine million, nine hundred twenty-one thousand, five hundred ninety-nine".