21001001101200 has 480 divisors, whose sum is σ = 78074525767680. Its totient is φ = 5351516121600.

The previous prime is 21001001101193. The next prime is 21001001101211. The reversal of 21001001101200 is 210110010012.

It is a happy number.

It is a super-2 number, since 2×21001001101200² (a number of 27 digits) contains 22 as substring.

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

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 95 ways as a sum of consecutive naturals, for example, 256059399 + ... + 256141401.

It is an arithmetic number, because the mean of its divisors is an integer number (162655262016).

Almost surely, 2^{21001001101200} is an apocalyptic number.

21001001101200 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 21001001101200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39037262883840).

21001001101200 is an abundant number, since it is smaller than the sum of its proper divisors (57073524666480).

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

21001001101200 is a wasteful number, since it uses less digits than its factorization.

21001001101200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83084 (or 83067 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

Adding to 21001001101200 its reverse (210110010012), we get a palindrome (21211111111212).

The spelling of 21001001101200 in words is "twenty-one trillion, one billion, one million, one hundred one thousand, two hundred".