21672479 has 8 divisors (see below), whose sum is σ = 22142160. Its totient is φ = 21208000.

The previous prime is 21672461. The next prime is 21672481. The reversal of 21672479 is 97427612.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21672479 - 2²⁰ = 20623903 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21672439) 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 7 ways as a sum of consecutive naturals, for example, 7784 + ... + 10194.

It is an arithmetic number, because the mean of its divisors is an integer number (2767770).

Almost surely, 2^21672479 is an apocalyptic number.

21672479 is a deficient number, since it is larger than the sum of its proper divisors (469681).

21672479 is a wasteful number, since it uses less digits than its factorization.

21672479 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2601.

The product of its digits is 42336, while the sum is 38.

The square root of 21672479 is about 4655.3709841429. The cubic root of 21672479 is about 278.8064801396.

The spelling of 21672479 in words is "twenty-one million, six hundred seventy-two thousand, four hundred seventy-nine".