21221002001100 has 144 divisors (see below), whose sum is σ = 66983127805440. Its totient is φ = 5144337196800.

The previous prime is 21221002001099. The next prime is 21221002001131. The reversal of 21221002001100 is 110020012212.

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

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 152750269 + ... + 152889131.

It is an arithmetic number, because the mean of its divisors is an integer number (465160609760).

Almost surely, 2^{21221002001100} is an apocalyptic number.

21221002001100 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21221002001100 is an abundant number, since it is smaller than the sum of its proper divisors (45762125804340).

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

21221002001100 is a wasteful number, since it uses less digits than its factorization.

21221002001100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 185200 (or 185193 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21221002001100 its reverse (110020012212), we get a palindrome (21331022013312).

The spelling of 21221002001100 in words is "twenty-one trillion, two hundred twenty-one billion, two million, one thousand, one hundred".