21221200121200 has 60 divisors (see below), whose sum is σ = 51556786560720. Its totient is φ = 8393103854080.

The previous prime is 21221200121171. The next prime is 21221200121201. The reversal of 21221200121200 is 212100212212.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21221200121201) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 298014964 + ... + 298086163.

It is an arithmetic number, because the mean of its divisors is an integer number (859279776012).

Almost surely, 2^{21221200121200} is an apocalyptic number.

21221200121200 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21221200121200 is an abundant number, since it is smaller than the sum of its proper divisors (30335586439520).

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

21221200121200 is a wasteful number, since it uses less digits than its factorization.

21221200121200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 596101234 (or 596101223 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21221200121200 its reverse (212100212212), we get a palindrome (21433300333412).

The spelling of 21221200121200 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred million, one hundred twenty-one thousand, two hundred".