21267216 has 30 divisors (see below), whose sum is σ = 59519070. Its totient is φ = 7089024.

The previous prime is 21267161. The next prime is 21267227. The reversal of 21267216 is 61276212.

It can be written as a sum of positive squares in only one way, i.e., 11532816 + 9734400 = 3396^2 + 3120^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21267216.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 73701 + ... + 73988.

It is an arithmetic number, because the mean of its divisors is an integer number (1983969).

Almost surely, 2^21267216 is an apocalyptic number.

It is an amenable number.

21267216 is an abundant number, since it is smaller than the sum of its proper divisors (38251854).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21267216 is a wasteful number, since it uses less digits than its factorization.

21267216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 147703 (or 147694 counting only the distinct ones).

The product of its digits is 2016, while the sum is 27.

The square root of 21267216 is about 4611.6391879678. The cubic root of 21267216 is about 277.0576932399.

The spelling of 21267216 in words is "twenty-one million, two hundred sixty-seven thousand, two hundred sixteen".