21279772 has 24 divisors (see below), whose sum is σ = 39415040. Its totient is φ = 10024560.

The previous prime is 21279757. The next prime is 21279781. The reversal of 21279772 is 27797212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15373 + ... + 16699.

Almost surely, 2^21279772 is an apocalyptic number.

It is an amenable number.

21279772 is a deficient number, since it is larger than the sum of its proper divisors (18135268).

21279772 is a wasteful number, since it uses less digits than its factorization.

21279772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1561 (or 1559 counting only the distinct ones).

The product of its digits is 24696, while the sum is 37.

The square root of 21279772 is about 4613.0003251680. Note that the first 3 decimals coincide. The cubic root of 21279772 is about 277.1122067536.

The spelling of 21279772 in words is "twenty-one million, two hundred seventy-nine thousand, seven hundred seventy-two".