21021020121020 has 96 divisors (see below), whose sum is σ = 44807905961280. Its totient is φ = 8282289899520.

The previous prime is 21021020120977. The next prime is 21021020121047. The reversal of 21021020121020 is 2012102012012.

It is a junction number, because it is equal to n+sod(n) for n = 21021020120986 and 21021020121004.

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, 5230408571 + ... + 5230412589.

It is an arithmetic number, because the mean of its divisors is an integer number (466749020430).

Almost surely, 2^{21021020121020} is an apocalyptic number.

21021020121020 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21021020121020 is an abundant number, since it is smaller than the sum of its proper divisors (23786885840260).

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

21021020121020 is a wasteful number, since it uses less digits than its factorization.

21021020121020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7935 (or 7933 counting only the distinct ones).

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

Adding to 21021020121020 its reverse (2012102012012), we get a palindrome (23033122133032).

The spelling of 21021020121020 in words is "twenty-one trillion, twenty-one billion, twenty million, one hundred twenty-one thousand, twenty".