21002121000000 has 588 divisors, whose sum is σ = 85997425468864. Its totient is φ = 4800470400000.

The previous prime is 21002120999999. The next prime is 21002121000013. The reversal of 21002121000000 is 12120012.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 83 ways as a sum of consecutive naturals, for example, 62833317 + ... + 63166683.

Almost surely, 2^{21002121000000} is an apocalyptic number.

21002121000000 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 21002121000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42998712734432).

21002121000000 is an abundant number, since it is smaller than the sum of its proper divisors (64995304468864).

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

21002121000000 is an frugal number, since it uses more digits than its factorization.

21002121000000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333422 (or 333384 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 21002121000000 its reverse (12120012), we get a palindrome (21002133120012).

The spelling of 21002121000000 in words is "twenty-one trillion, two billion, one hundred twenty-one million", and thus it is an aban number.