21672272 has 20 divisors (see below), whose sum is σ = 43015476. Its totient is φ = 10571520.

The previous prime is 21672271. The next prime is 21672319. The reversal of 21672272 is 27227612.

It can be written as a sum of positive squares in 2 ways, for example, as 364816 + 21307456 = 604^2 + 4616^2 .

It is a Smith number, since the sum of its digits (29) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21672271) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15863 + ... + 17174.

Almost surely, 2^21672272 is an apocalyptic number.

It is an amenable number.

21672272 is a deficient number, since it is larger than the sum of its proper divisors (21343204).

21672272 is a wasteful number, since it uses less digits than its factorization.

21672272 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33086 (or 33080 counting only the distinct ones).

The product of its digits is 4704, while the sum is 29.

The square root of 21672272 is about 4655.3487517049. The cubic root of 21672272 is about 278.8055924835.

Adding to 21672272 its reverse (27227612), we get a palindrome (48899884).

The spelling of 21672272 in words is "twenty-one million, six hundred seventy-two thousand, two hundred seventy-two".