21100099 has 4 divisors (see below), whose sum is σ = 21150640. Its totient is φ = 21049560.

The previous prime is 21100097. The next prime is 21100103. The reversal of 21100099 is 99000112.

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 21100099 - 2¹ = 21100097 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21100097) 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, 24639 + ... + 25480.

It is an arithmetic number, because the mean of its divisors is an integer number (5287660).

Almost surely, 2^21100099 is an apocalyptic number.

21100099 is a deficient number, since it is larger than the sum of its proper divisors (50541).

21100099 is an equidigital number, since it uses as much as digits as its factorization.

21100099 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50540.

The product of its (nonzero) digits is 162, while the sum is 22.

The square root of 21100099 is about 4593.4844072882. The cubic root of 21100099 is about 276.3300809991.

The spelling of 21100099 in words is "twenty-one million, one hundred thousand, ninety-nine".