21653272 has 16 divisors (see below), whose sum is σ = 40829400. Its totient is φ = 10765440.

The previous prime is 21653267. The next prime is 21653279. The reversal of 21653272 is 27235612.

It is a self number, because there is not a number n which added to its sum of digits gives 21653272.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21653279) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 6129 + ... + 8992.

Almost surely, 2^21653272 is an apocalyptic number.

It is an amenable number.

21653272 is a deficient number, since it is larger than the sum of its proper divisors (19176128).

21653272 is a wasteful number, since it uses less digits than its factorization.

21653272 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15306 (or 15302 counting only the distinct ones).

The product of its digits is 5040, while the sum is 28.

The square root of 21653272 is about 4653.3076408078. The cubic root of 21653272 is about 278.7240927212.

Adding to 21653272 its reverse (27235612), we get a palindrome (48888884).

The spelling of 21653272 in words is "twenty-one million, six hundred fifty-three thousand, two hundred seventy-two".