21565852 has 24 divisors (see below), whose sum is σ = 47053440. Its totient is φ = 8402160.

The previous prime is 21565849. The next prime is 21565853. The reversal of 21565852 is 25856512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21565853) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 34702 + ... + 35317.

It is an arithmetic number, because the mean of its divisors is an integer number (1960560).

Almost surely, 2^21565852 is an apocalyptic number.

21565852 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21565852 is an abundant number, since it is smaller than the sum of its proper divisors (25487588).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21565852 is a wasteful number, since it uses less digits than its factorization.

21565852 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70041 (or 70039 counting only the distinct ones).

The product of its digits is 24000, while the sum is 34.

The square root of 21565852 is about 4643.9048224528. The cubic root of 21565852 is about 278.3484924473.

It can be divided in two parts, 2156 and 5852, that added together give a palindrome (8008).

The spelling of 21565852 in words is "twenty-one million, five hundred sixty-five thousand, eight hundred fifty-two".