21360739 has 4 divisors (see below), whose sum is σ = 21679624. Its totient is φ = 21041856.

The previous prime is 21360709. The next prime is 21360743. The reversal of 21360739 is 93706312.

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 21360739 - 2⁵ = 21360707 is a prime.

It is a super-2 number, since 2×21360739² = 912562341252242, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21360739.

It is not an unprimeable number, because it can be changed into a prime (21360709) 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, 159342 + ... + 159475.

It is an arithmetic number, because the mean of its divisors is an integer number (5419906).

Almost surely, 2^21360739 is an apocalyptic number.

21360739 is a deficient number, since it is larger than the sum of its proper divisors (318885).

21360739 is an equidigital number, since it uses as much as digits as its factorization.

21360739 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 318884.

The product of its (nonzero) digits is 6804, while the sum is 31.

The square root of 21360739 is about 4621.7679517691. The cubic root of 21360739 is about 277.4632215955.

The spelling of 21360739 in words is "twenty-one million, three hundred sixty thousand, seven hundred thirty-nine".