21288852 has 96 divisors (see below), whose sum is σ = 60681600. Its totient is φ = 6414336.

The previous prime is 21288851. The next prime is 21288857. The reversal of 21288852 is 25888212.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21288851) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 82708 + ... + 82964.

It is an arithmetic number, because the mean of its divisors is an integer number (632100).

Almost surely, 2^21288852 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21288852, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30340800).

21288852 is an abundant number, since it is smaller than the sum of its proper divisors (39392748).

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

21288852 is a wasteful number, since it uses less digits than its factorization.

21288852 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 342 (or 334 counting only the distinct ones).

The product of its digits is 20480, while the sum is 36.

The square root of 21288852 is about 4613.9843952922. The cubic root of 21288852 is about 277.1516154002.

The spelling of 21288852 in words is "twenty-one million, two hundred eighty-eight thousand, eight hundred fifty-two".