21272236 has 24 divisors (see below), whose sum is σ = 39901680. Its totient is φ = 9887232.

The previous prime is 21272213. The next prime is 21272269. The reversal of 21272236 is 63227212.

It is a self number, because there is not a number n which added to its sum of digits gives 21272236.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3760 + ... + 7528.

It is an arithmetic number, because the mean of its divisors is an integer number (1662570).

Almost surely, 2^21272236 is an apocalyptic number.

It is an amenable number.

21272236 is a deficient number, since it is larger than the sum of its proper divisors (18629444).

21272236 is a wasteful number, since it uses less digits than its factorization.

21272236 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3873 (or 3871 counting only the distinct ones).

The product of its digits is 2016, while the sum is 25.

The square root of 21272236 is about 4612.1834308709. The cubic root of 21272236 is about 277.0794907992.

Adding to 21272236 its reverse (63227212), we get a palindrome (84499448).

The spelling of 21272236 in words is "twenty-one million, two hundred seventy-two thousand, two hundred thirty-six".