21002221312 has 72 divisors (see below), whose sum is σ = 43424493840. Its totient is φ = 10125803520.

The previous prime is 21002221309. The next prime is 21002221333. The reversal of 21002221312 is 21312220012.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8098288 + ... + 8100880.

It is an arithmetic number, because the mean of its divisors is an integer number (603117970).

Almost surely, 2^21002221312 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 21002221312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21712246920).

21002221312 is an abundant number, since it is smaller than the sum of its proper divisors (22422272528).

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

21002221312 is a wasteful number, since it uses less digits than its factorization.

21002221312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3729 (or 3715 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 16.

Adding to 21002221312 its reverse (21312220012), we get a palindrome (42314441324).

The spelling of 21002221312 in words is "twenty-one billion, two million, two hundred twenty-one thousand, three hundred twelve".