99921601 has 4 divisors (see below), whose sum is σ = 107607892. Its totient is φ = 92235312.

The previous prime is 99921533. The next prime is 99921607. The reversal of 99921601 is 10612999.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 58125376 + 41796225 = 7624^2 + 6465^2 .

It is not a de Polignac number, because 99921601 - 2⁷ = 99921473 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (99921607) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3843126 + ... + 3843151.

It is an arithmetic number, because the mean of its divisors is an integer number (26901973).

Almost surely, 2^99921601 is an apocalyptic number.

It is an amenable number.

99921601 is a deficient number, since it is larger than the sum of its proper divisors (7686291).

99921601 is a wasteful number, since it uses less digits than its factorization.

99921601 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7686290.

The product of its (nonzero) digits is 8748, while the sum is 37.

The square root of 99921601 is about 9996.0792813983. The cubic root of 99921601 is about 464.0375530075.

The spelling of 99921601 in words is "ninety-nine million, nine hundred twenty-one thousand, six hundred one".