21021121020020 has 48 divisors (see below), whose sum is σ = 48973705704000. Its totient is φ = 7514483934720.

The previous prime is 21021121019993. The next prime is 21021121020023. The reversal of 21021121020020 is 2002012112012.

It is a junction number, because it is equal to n+sod(n) for n = 21021121019977 and 21021121020004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021121020023) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 809737445 + ... + 809763404.

It is an arithmetic number, because the mean of its divisors is an integer number (1020285535500).

Almost surely, 2^{21021121020020} is an apocalyptic number.

21021121020020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21021121020020 is an abundant number, since it is smaller than the sum of its proper divisors (27952584683980).

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

21021121020020 is a wasteful number, since it uses less digits than its factorization.

21021121020020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1619500928 (or 1619500926 counting only the distinct ones).

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

Adding to 21021121020020 its reverse (2002012112012), we get a palindrome (23023133132032).

The spelling of 21021121020020 in words is "twenty-one trillion, twenty-one billion, one hundred twenty-one million, twenty thousand, twenty".