21316727 has 4 divisors (see below), whose sum is σ = 22438680. Its totient is φ = 20194776.

The previous prime is 21316723. The next prime is 21316739. The reversal of 21316727 is 72761312.

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 21316727 - 2² = 21316723 is a prime.

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 21316727.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21316721) 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, 560948 + ... + 560985.

It is an arithmetic number, because the mean of its divisors is an integer number (5609670).

Almost surely, 2^21316727 is an apocalyptic number.

21316727 is a deficient number, since it is larger than the sum of its proper divisors (1121953).

21316727 is a wasteful number, since it uses less digits than its factorization.

21316727 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1121952.

The product of its digits is 3528, while the sum is 29.

The square root of 21316727 is about 4617.0041152245. The cubic root of 21316727 is about 277.2725273817.

The spelling of 21316727 in words is "twenty-one million, three hundred sixteen thousand, seven hundred twenty-seven".