21989312 has 14 divisors (see below), whose sum is σ = 43635168. Its totient is φ = 10994624.

The previous prime is 21989291. The next prime is 21989369. The reversal of 21989312 is 21398912.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 171728 + ... + 171855.

Almost surely, 2^21989312 is an apocalyptic number.

It is an amenable number.

21989312 is a deficient number, since it is larger than the sum of its proper divisors (21645856).

21989312 is an equidigital number, since it uses as much as digits as its factorization.

21989312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 343595 (or 343585 counting only the distinct ones).

The product of its digits is 7776, while the sum is 35.

The square root of 21989312 is about 4689.2762767830. The cubic root of 21989312 is about 280.1585496603.

The spelling of 21989312 in words is "twenty-one million, nine hundred eighty-nine thousand, three hundred twelve".