21525844 has 12 divisors (see below), whose sum is σ = 38381364. Its totient is φ = 10559744.

The previous prime is 21525793. The next prime is 21525853. The reversal of 21525844 is 44852512.

It can be written as a sum of positive squares in 2 ways, for example, as 18147600 + 3378244 = 4260^2 + 1838^2 .

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, 50557 + ... + 50980.

It is an arithmetic number, because the mean of its divisors is an integer number (3198447).

Almost surely, 2^21525844 is an apocalyptic number.

It is an amenable number.

21525844 is a deficient number, since it is larger than the sum of its proper divisors (16855520).

21525844 is a wasteful number, since it uses less digits than its factorization.

21525844 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 101594 (or 101592 counting only the distinct ones).

The product of its digits is 12800, while the sum is 31.

The square root of 21525844 is about 4639.5952409666. The cubic root of 21525844 is about 278.1762593566.

The spelling of 21525844 in words is "twenty-one million, five hundred twenty-five thousand, eight hundred forty-four".