21108079 has 4 divisors (see below), whose sum is σ = 21174984. Its totient is φ = 21041176.

The previous prime is 21108077. The next prime is 21108083. The reversal of 21108079 is 97080112.

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 21108079 - 2¹ = 21108077 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21108077) 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, 32977 + ... + 33610.

It is an arithmetic number, because the mean of its divisors is an integer number (5293746).

Almost surely, 2^21108079 is an apocalyptic number.

21108079 is a deficient number, since it is larger than the sum of its proper divisors (66905).

21108079 is an equidigital number, since it uses as much as digits as its factorization.

21108079 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 66904.

The product of its (nonzero) digits is 1008, while the sum is 28.

The square root of 21108079 is about 4594.3529468250. The cubic root of 21108079 is about 276.3649123699.

The spelling of 21108079 in words is "twenty-one million, one hundred eight thousand, seventy-nine".