21012003323220 has 384 divisors, whose sum is σ = 73603926789120. Its totient is φ = 4360757575680.

The previous prime is 21012003323191. The next prime is 21012003323321. The reversal of 21012003323220 is 2232330021012.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 93674400 + ... + 93898440.

It is an arithmetic number, because the mean of its divisors is an integer number (191676892680).

Almost surely, 2^{21012003323220} is an apocalyptic number.

21012003323220 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 21012003323220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36801963394560).

21012003323220 is an abundant number, since it is smaller than the sum of its proper divisors (52591923465900).

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

21012003323220 is a wasteful number, since it uses less digits than its factorization.

21012003323220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 224355 (or 224353 counting only the distinct ones).

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

Adding to 21012003323220 its reverse (2232330021012), we get a palindrome (23244333344232).

The spelling of 21012003323220 in words is "twenty-one trillion, twelve billion, three million, three hundred twenty-three thousand, two hundred twenty".