21000021021200 has 120 divisors (see below), whose sum is σ = 54371084486208. Its totient is φ = 7748492567040.

The previous prime is 21000021021193. The next prime is 21000021021211. The reversal of 21000021021200 is 212012000012.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6128939 + ... + 8919861.

Almost surely, 2^{21000021021200} is an apocalyptic number.

21000021021200 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 21000021021200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27185542243104).

21000021021200 is an abundant number, since it is smaller than the sum of its proper divisors (33371063465008).

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

21000021021200 is a wasteful number, since it uses less digits than its factorization.

21000021021200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2792401 (or 2792390 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 21000021021200 its reverse (212012000012), we get a palindrome (21212033021212).

The spelling of 21000021021200 in words is "twenty-one trillion, twenty-one million, twenty-one thousand, two hundred".