21101211001200 has 480 divisors, whose sum is σ = 74513030860800. Its totient is φ = 5061818880000.

The previous prime is 21101211001187. The next prime is 21101211001223. The reversal of 21101211001200 is 210011210112.

It is a super-2 number, since 2×21101211001200² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 2985031266 + ... + 2985038334.

It is an arithmetic number, because the mean of its divisors is an integer number (155235480960).

Almost surely, 2^{21101211001200} is an apocalyptic number.

21101211001200 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 21101211001200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37256515430400).

21101211001200 is an abundant number, since it is smaller than the sum of its proper divisors (53411819859600).

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

21101211001200 is a wasteful number, since it uses less digits than its factorization.

21101211001200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9441 (or 9430 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21101211001200 its reverse (210011210112), we get a palindrome (21311222211312).

The spelling of 21101211001200 in words is "twenty-one trillion, one hundred one billion, two hundred eleven million, one thousand, two hundred".