21989712 has 20 divisors (see below), whose sum is σ = 56806880. Its totient is φ = 7329888.

The previous prime is 21989701. The next prime is 21989741. The reversal of 21989712 is 21798912.

It is a Smith number, since the sum of its digits (39) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is an unprimeable number.

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, 229012 + ... + 229107.

It is an arithmetic number, because the mean of its divisors is an integer number (2840344).

Almost surely, 2^21989712 is an apocalyptic number.

It is an amenable number.

21989712 is an abundant number, since it is smaller than the sum of its proper divisors (34817168).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21989712 is a wasteful number, since it uses less digits than its factorization.

21989712 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 458130 (or 458124 counting only the distinct ones).

The product of its digits is 18144, while the sum is 39.

The square root of 21989712 is about 4689.3189270938. The cubic root of 21989712 is about 280.1602484059.

The spelling of 21989712 in words is "twenty-one million, nine hundred eighty-nine thousand, seven hundred twelve".