21895724 has 12 divisors (see below), whose sum is σ = 39983664. Its totient is φ = 10471824.

The previous prime is 21895723. The next prime is 21895759. The reversal of 21895724 is 42759812.

It is not an unprimeable number, because it can be changed into a prime (21895721) by changing a digit.

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, 118907 + ... + 119090.

It is an arithmetic number, because the mean of its divisors is an integer number (3331972).

Almost surely, 2^21895724 is an apocalyptic number.

It is an amenable number.

21895724 is a deficient number, since it is larger than the sum of its proper divisors (18087940).

21895724 is a wasteful number, since it uses less digits than its factorization.

21895724 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 238024 (or 238022 counting only the distinct ones).

The product of its digits is 40320, while the sum is 38.

The square root of 21895724 is about 4679.2866977778. The cubic root of 21895724 is about 279.7605265383.

The spelling of 21895724 in words is "twenty-one million, eight hundred ninety-five thousand, seven hundred twenty-four".