21001210221020 has 24 divisors (see below), whose sum is σ = 44107278461568. Its totient is φ = 8399581803200.

The previous prime is 21001210220957. The next prime is 21001210221029. The reversal of 21001210221020 is 2012201210012.

It is a junction number, because it is equal to n+sod(n) for n = 21001210220986 and 21001210221004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001210221029) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 56201951 + ... + 56574390.

It is an arithmetic number, because the mean of its divisors is an integer number (1837803269232).

Almost surely, 2^{21001210221020} is an apocalyptic number.

21001210221020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21001210221020 is an abundant number, since it is smaller than the sum of its proper divisors (23106068240548).

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

21001210221020 is a wasteful number, since it uses less digits than its factorization.

21001210221020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 112785661 (or 112785659 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21001210221020 its reverse (2012201210012), we get a palindrome (23013411431032).

The spelling of 21001210221020 in words is "twenty-one trillion, one billion, two hundred ten million, two hundred twenty-one thousand, twenty".