21364999 has 4 divisors (see below), whose sum is σ = 22293936. Its totient is φ = 20436064.

The previous prime is 21364991. The next prime is 21365009. The reversal of 21364999 is 99946312.

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 21364999 - 2³ = 21364991 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 (21364991) 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, 464434 + ... + 464479.

It is an arithmetic number, because the mean of its divisors is an integer number (5573484).

Almost surely, 2^21364999 is an apocalyptic number.

21364999 is a deficient number, since it is larger than the sum of its proper divisors (928937).

21364999 is an equidigital number, since it uses as much as digits as its factorization.

21364999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 928936.

The product of its digits is 104976, while the sum is 43.

The square root of 21364999 is about 4622.2287913949. The cubic root of 21364999 is about 277.4816653200.

The spelling of 21364999 in words is "twenty-one million, three hundred sixty-four thousand, nine hundred ninety-nine".