21579916 has 6 divisors (see below), whose sum is σ = 37764860. Its totient is φ = 10789956.

The previous prime is 21579913. The next prime is 21579931. The reversal of 21579916 is 61997512.

It is not an unprimeable number, because it can be changed into a prime (21579913) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2697486 + ... + 2697493.

Almost surely, 2^21579916 is an apocalyptic number.

It is an amenable number.

21579916 is a deficient number, since it is larger than the sum of its proper divisors (16184944).

21579916 is a wasteful number, since it uses less digits than its factorization.

21579916 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5394983 (or 5394981 counting only the distinct ones).

The product of its digits is 34020, while the sum is 40.

The square root of 21579916 is about 4645.4188185781. The cubic root of 21579916 is about 278.4089868890.

The spelling of 21579916 in words is "twenty-one million, five hundred seventy-nine thousand, nine hundred sixteen".