21020121100000 has 288 divisors, whose sum is σ = 56802393414144. Its totient is φ = 7593000000000.

The previous prime is 21020121099979. The next prime is 21020121100057. The reversal of 21020121100000 is 112102012.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a self number, because there is not a number n which added to its sum of digits gives 21020121100000.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 166036725 + ... + 166163275.

It is an arithmetic number, because the mean of its divisors is an integer number (197230532688).

Almost surely, 2^{21020121100000} is an apocalyptic number.

21020121100000 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 21020121100000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28401196707072).

21020121100000 is an abundant number, since it is smaller than the sum of its proper divisors (35782272314144).

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

21020121100000 is a wasteful number, since it uses less digits than its factorization.

21020121100000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126748 (or 126720 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 21020121100000 its reverse (112102012), we get a palindrome (21020233202012).

The spelling of 21020121100000 in words is "twenty-one trillion, twenty billion, one hundred twenty-one million, one hundred thousand".