21272732 has 24 divisors (see below), whose sum is σ = 40249776. Its totient is φ = 9779328.

The previous prime is 21272731. The next prime is 21272759. The reversal of 21272732 is 23727212.

It is a Smith number, since the sum of its digits (26) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21272731) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15623 + ... + 16929.

It is an arithmetic number, because the mean of its divisors is an integer number (1677074).

Almost surely, 2^21272732 is an apocalyptic number.

It is an amenable number.

21272732 is a deficient number, since it is larger than the sum of its proper divisors (18977044).

21272732 is a wasteful number, since it uses less digits than its factorization.

21272732 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1637 (or 1635 counting only the distinct ones).

The product of its digits is 2352, while the sum is 26.

The square root of 21272732 is about 4612.2372011856. The cubic root of 21272732 is about 277.0816443161.

Adding to 21272732 its reverse (23727212), we get a palindrome (44999944).

The spelling of 21272732 in words is "twenty-one million, two hundred seventy-two thousand, seven hundred thirty-two".