21316679 has 4 divisors (see below), whose sum is σ = 21836640. Its totient is φ = 20796720.

The previous prime is 21316667. The next prime is 21316693. The reversal of 21316679 is 97661312.

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 21316679 - 2⁴ = 21316663 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 (21316609) 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, 259919 + ... + 260000.

It is an arithmetic number, because the mean of its divisors is an integer number (5459160).

Almost surely, 2^21316679 is an apocalyptic number.

21316679 is a deficient number, since it is larger than the sum of its proper divisors (519961).

21316679 is an equidigital number, since it uses as much as digits as its factorization.

21316679 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 519960.

The product of its digits is 13608, while the sum is 35.

The square root of 21316679 is about 4616.9989170456. The cubic root of 21316679 is about 277.2723192652.

The spelling of 21316679 in words is "twenty-one million, three hundred sixteen thousand, six hundred seventy-nine".