21365099 has 4 divisors (see below), whose sum is σ = 24417264. Its totient is φ = 18312936.

The previous prime is 21365093. The next prime is 21365117. The reversal of 21365099 is 99056312.

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 21365099 - 2¹² = 21361003 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21365093) 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, 1526072 + ... + 1526085.

It is an arithmetic number, because the mean of its divisors is an integer number (6104316).

Almost surely, 2^21365099 is an apocalyptic number.

21365099 is a deficient number, since it is larger than the sum of its proper divisors (3052165).

21365099 is an equidigital number, since it uses as much as digits as its factorization.

21365099 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3052164.

The product of its (nonzero) digits is 14580, while the sum is 35.

The square root of 21365099 is about 4622.2396086746. The cubic root of 21365099 is about 277.4820982419.

The spelling of 21365099 in words is "twenty-one million, three hundred sixty-five thousand, ninety-nine".