21210000252 has 288 divisors, whose sum is σ = 61953196032. Its totient is φ = 5618156544.

The previous prime is 21210000209. The next prime is 21210000271. The reversal of 21210000252 is 25200001212.

It is a super-2 number, since 2×21210000252² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 91029928 + ... + 91030160.

It is an arithmetic number, because the mean of its divisors is an integer number (215115264).

Almost surely, 2^21210000252 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 21210000252, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30976598016).

21210000252 is an abundant number, since it is smaller than the sum of its proper divisors (40743195780).

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

21210000252 is a wasteful number, since it uses less digits than its factorization.

21210000252 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 457 (or 448 counting only the distinct ones).

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

Adding to 21210000252 its reverse (25200001212), we get a palindrome (46410001464).

The spelling of 21210000252 in words is "twenty-one billion, two hundred ten million, two hundred fifty-two", and thus it is an aban number.