21000122121120 has 192 divisors, whose sum is σ = 67809003655680. Its totient is φ = 5460506329088.

The previous prime is 21000122121109. The next prime is 21000122121169. The reversal of 21000122121120 is 2112122100012.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21000122121120.

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, 4338424 + ... + 7798856.

It is an arithmetic number, because the mean of its divisors is an integer number (353171894040).

Almost surely, 2^{21000122121120} is an apocalyptic number.

21000122121120 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 21000122121120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33904501827840).

21000122121120 is an abundant number, since it is smaller than the sum of its proper divisors (46808881534560).

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

21000122121120 is a wasteful number, since it uses less digits than its factorization.

21000122121120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3460767 (or 3460759 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21000122121120 its reverse (2112122100012), we get a palindrome (23112244221132).

The spelling of 21000122121120 in words is "twenty-one trillion, one hundred twenty-two million, one hundred twenty-one thousand, one hundred twenty".