21312102020 has 192 divisors, whose sum is σ = 54750608640. Its totient is φ = 6867763200.

The previous prime is 21312101983. The next prime is 21312102041. The reversal of 21312102020 is 2020121312.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21312101986 and 21312102004.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 12861032 + ... + 12862688.

It is an arithmetic number, because the mean of its divisors is an integer number (285159420).

Almost surely, 2^21312102020 is an apocalyptic number.

21312102020 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 21312102020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27375304320).

21312102020 is an abundant number, since it is smaller than the sum of its proper divisors (33438506620).

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

21312102020 is a wasteful number, since it uses less digits than its factorization.

21312102020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1894 (or 1892 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 14.

Adding to 21312102020 its reverse (2020121312), we get a palindrome (23332223332).

The spelling of 21312102020 in words is "twenty-one billion, three hundred twelve million, one hundred two thousand, twenty".