21210253312 has 48 divisors (see below), whose sum is σ = 42442955100. Its totient is φ = 10596925440.

The previous prime is 21210253277. The next prime is 21210253319. The reversal of 21210253312 is 21335201212.

It can be written as a sum of positive squares in 2 ways, for example, as 20159456256 + 1050797056 = 141984^2 + 32416^2 .

It is not an unprimeable number, because it can be changed into a prime (21210253319) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3316614 + ... + 3323002.

Almost surely, 2^21210253312 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 21210253312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21221477550).

21210253312 is an abundant number, since it is smaller than the sum of its proper divisors (21232701788).

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

21210253312 is an equidigital number, since it uses as much as digits as its factorization.

21210253312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8032 (or 8012 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 22.

Adding to 21210253312 its reverse (21335201212), we get a palindrome (42545454524).

The spelling of 21210253312 in words is "twenty-one billion, two hundred ten million, two hundred fifty-three thousand, three hundred twelve".