21775244 has 12 divisors (see below), whose sum is σ = 38589600. Its totient is φ = 10749648.

The previous prime is 21775219. The next prime is 21775261. The reversal of 21775244 is 44257712.

It is a super-2 number, since 2×21775244² = 948322502519072, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21775244.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34139 + ... + 34770.

It is an arithmetic number, because the mean of its divisors is an integer number (3215800).

Almost surely, 2^21775244 is an apocalyptic number.

It is an amenable number.

21775244 is a deficient number, since it is larger than the sum of its proper divisors (16814356).

21775244 is a wasteful number, since it uses less digits than its factorization.

21775244 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68992 (or 68990 counting only the distinct ones).

The product of its digits is 15680, while the sum is 32.

The square root of 21775244 is about 4666.3951825794. The cubic root of 21775244 is about 279.2464602776.

The spelling of 21775244 in words is "twenty-one million, seven hundred seventy-five thousand, two hundred forty-four".