21012252 has 48 divisors (see below), whose sum is σ = 52026240. Its totient is φ = 6581952.

The previous prime is 21012241. The next prime is 21012259. The reversal of 21012252 is 25221012.

It is a super-2 number, since 2×21012252² = 883029468223008, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012259) 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 15 ways as a sum of consecutive naturals, for example, 35503 + ... + 36089.

It is an arithmetic number, because the mean of its divisors is an integer number (1083880).

Almost surely, 2^21012252 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 21012252, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26013120).

21012252 is an abundant number, since it is smaller than the sum of its proper divisors (31013988).

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

21012252 is a wasteful number, since it uses less digits than its factorization.

21012252 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 770 (or 768 counting only the distinct ones).

The product of its (nonzero) digits is 80, while the sum is 15.

The square root of 21012252 is about 4583.9123028260. The cubic root of 21012252 is about 275.9460617133.

Adding to 21012252 its reverse (25221012), we get a palindrome (46233264).

The spelling of 21012252 in words is "twenty-one million, twelve thousand, two hundred fifty-two".