21213223320 has 128 divisors (see below), whose sum is σ = 65939624640. Its totient is φ = 5455134720.

The previous prime is 21213223307. The next prime is 21213223391. The reversal of 21213223320 is 2332231212.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 480580 + ... + 522860.

Almost surely, 2^21213223320 is an apocalyptic number.

21213223320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21213223320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32969812320).

21213223320 is an abundant number, since it is smaller than the sum of its proper divisors (44726401320).

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

21213223320 is a wasteful number, since it uses less digits than its factorization.

21213223320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42445 (or 42441 counting only the distinct ones).

The product of its (nonzero) digits is 864, while the sum is 21.

Adding to 21213223320 its reverse (2332231212), we get a palindrome (23545454532).

The spelling of 21213223320 in words is "twenty-one billion, two hundred thirteen million, two hundred twenty-three thousand, three hundred twenty".