21915772 has 12 divisors (see below), whose sum is σ = 38459680. Its totient is φ = 10927296.

The previous prime is 21915769. The next prime is 21915779. The reversal of 21915772 is 27751912.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21915779) 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 3 ways as a sum of consecutive naturals, for example, 5997 + ... + 8932.

Almost surely, 2^21915772 is an apocalyptic number.

It is an amenable number.

21915772 is a deficient number, since it is larger than the sum of its proper divisors (16543908).

21915772 is a wasteful number, since it uses less digits than its factorization.

21915772 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15300 (or 15298 counting only the distinct ones).

The product of its digits is 8820, while the sum is 34.

The square root of 21915772 is about 4681.4284144906. The cubic root of 21915772 is about 279.8458845763.

The spelling of 21915772 in words is "twenty-one million, nine hundred fifteen thousand, seven hundred seventy-two".