21865252 has 24 divisors (see below), whose sum is σ = 39218816. Its totient is φ = 10663488.

The previous prime is 21865243. The next prime is 21865279. The reversal of 21865252 is 25256812.

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 7 ways as a sum of consecutive naturals, for example, 29713 + ... + 30439.

Almost surely, 2^21865252 is an apocalyptic number.

It is an amenable number.

21865252 is a deficient number, since it is larger than the sum of its proper divisors (17353564).

21865252 is a wasteful number, since it uses less digits than its factorization.

21865252 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 907 (or 905 counting only the distinct ones).

The product of its digits is 9600, while the sum is 31.

The square root of 21865252 is about 4676.0295123106. The cubic root of 21865252 is about 279.6306865678.

The spelling of 21865252 in words is "twenty-one million, eight hundred sixty-five thousand, two hundred fifty-two".