21267715 has 16 divisors (see below), whose sum is σ = 29764800. Its totient is φ = 14582400.

The previous prime is 21267713. The next prime is 21267721. The reversal of 21267715 is 51776212.

It is not a de Polignac number, because 21267715 - 2¹ = 21267713 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21267713) 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, 4486 + ... + 7915.

It is an arithmetic number, because the mean of its divisors is an integer number (1860300).

Almost surely, 2^21267715 is an apocalyptic number.

21267715 is a deficient number, since it is larger than the sum of its proper divisors (8497085).

21267715 is an equidigital number, since it uses as much as digits as its factorization.

21267715 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12427 (or 12413 counting only the distinct ones).

The product of its digits is 5880, while the sum is 31.

The square root of 21267715 is about 4611.6932898882. The cubic root of 21267715 is about 277.0598601229.

The spelling of 21267715 in words is "twenty-one million, two hundred sixty-seven thousand, seven hundred fifteen".