21101212221220 has 48 divisors (see below), whose sum is σ = 44452220537088. Its totient is φ = 8413889379840.

The previous prime is 21101212221181. The next prime is 21101212221311. The reversal of 21101212221220 is 2212221210112.

It is a super-2 number, since 2×21101212221220² (a number of 27 digits) contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 36669925 + ... + 37240915.

It is an arithmetic number, because the mean of its divisors is an integer number (926087927856).

Almost surely, 2^{21101212221220} is an apocalyptic number.

21101212221220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21101212221220 is an abundant number, since it is smaller than the sum of its proper divisors (23351008315868).

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

21101212221220 is a wasteful number, since it uses less digits than its factorization.

21101212221220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 576820 (or 576818 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 19.

Adding to 21101212221220 its reverse (2212221210112), we get a palindrome (23313433431332).

The spelling of 21101212221220 in words is "twenty-one trillion, one hundred one billion, two hundred twelve million, two hundred twenty-one thousand, two hundred twenty".