21993099 has 4 divisors (see below), whose sum is σ = 29324136. Its totient is φ = 14662064.

The previous prime is 21993079. The next prime is 21993109. The reversal of 21993099 is 99039912.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 21993099 - 2⁵ = 21993067 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21993099.

It is not an unprimeable number, because it can be changed into a prime (21993079) 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, 3665514 + ... + 3665519.

It is an arithmetic number, because the mean of its divisors is an integer number (7331034).

Almost surely, 2^21993099 is an apocalyptic number.

21993099 is a deficient number, since it is larger than the sum of its proper divisors (7331037).

21993099 is an equidigital number, since it uses as much as digits as its factorization.

21993099 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7331036.

The product of its (nonzero) digits is 39366, while the sum is 42.

The square root of 21993099 is about 4689.6800530527. The cubic root of 21993099 is about 280.1746317085.

The spelling of 21993099 in words is "twenty-one million, nine hundred ninety-three thousand, ninety-nine".