21672279 has 20 divisors (see below), whose sum is σ = 33785136. Its totient is φ = 13818816.

The previous prime is 21672271. The next prime is 21672319. The reversal of 21672279 is 97227612.

It is not a de Polignac number, because 21672279 - 2³ = 21672271 is a prime.

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 pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 3954 + ... + 7679.

Almost surely, 2^21672279 is an apocalyptic number.

21672279 is a deficient number, since it is larger than the sum of its proper divisors (12112857).

21672279 is a wasteful number, since it uses less digits than its factorization.

21672279 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11668 (or 11659 counting only the distinct ones).

The product of its digits is 21168, while the sum is 36.

The square root of 21672279 is about 4655.3495035282. The cubic root of 21672279 is about 278.8056225010.

The spelling of 21672279 in words is "twenty-one million, six hundred seventy-two thousand, two hundred seventy-nine".