21396727 has 16 divisors (see below), whose sum is σ = 25519104. Its totient is φ = 17712000.

The previous prime is 21396709. The next prime is 21396731. The reversal of 21396727 is 72769312.

21396727 is nontrivially palindromic in base 5.

It is a cyclic number.

It is not a de Polignac number, because 21396727 - 2¹¹ = 21394679 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 (21396827) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3952 + ... + 7642.

It is an arithmetic number, because the mean of its divisors is an integer number (1594944).

Almost surely, 2^21396727 is an apocalyptic number.

21396727 is a deficient number, since it is larger than the sum of its proper divisors (4122377).

21396727 is a wasteful number, since it uses less digits than its factorization.

21396727 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3750.

The product of its digits is 31752, while the sum is 37.

The square root of 21396727 is about 4625.6596286368. The cubic root of 21396727 is about 277.6189550337.

The spelling of 21396727 in words is "twenty-one million, three hundred ninety-six thousand, seven hundred twenty-seven".