99998921 has 4 divisors (see below), whose sum is σ = 109089744. Its totient is φ = 90908100.

The previous prime is 99998909. The next prime is 99998929. The reversal of 99998921 is 12989999.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 99998921 - 2¹⁰ = 99997897 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (99998929) 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 3 ways as a sum of consecutive naturals, for example, 4545395 + ... + 4545416.

It is an arithmetic number, because the mean of its divisors is an integer number (27272436).

Almost surely, 2^99998921 is an apocalyptic number.

It is an amenable number.

99998921 is a deficient number, since it is larger than the sum of its proper divisors (9090823).

99998921 is a wasteful number, since it uses less digits than its factorization.

99998921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9090822.

The product of its digits is 944784, while the sum is 56.

The square root of 99998921 is about 9999.9460498545. The cubic root of 99998921 is about 464.1572139305.

The spelling of 99998921 in words is "ninety-nine million, nine hundred ninety-eight thousand, nine hundred twenty-one".