21101222101220 has 24 divisors (see below), whose sum is σ = 44340313860024. Its totient is φ = 8435203612416.

The previous prime is 21101222101177. The next prime is 21101222101277. The reversal of 21101222101220 is 2210122210112.

It can be written as a sum of positive squares in 4 ways, for example, as 5289926400256 + 15811295700964 = 2299984^2 + 3976342^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 330294017 + ... + 330357896.

It is an arithmetic number, because the mean of its divisors is an integer number (1847513077501).

Almost surely, 2^{21101222101220} is an apocalyptic number.

21101222101220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21101222101220 is an abundant number, since it is smaller than the sum of its proper divisors (23239091758804).

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

21101222101220 is a wasteful number, since it uses less digits than its factorization.

21101222101220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 660653519 (or 660653517 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 21101222101220 its reverse (2210122210112), we get a palindrome (23311344311332).

The spelling of 21101222101220 in words is "twenty-one trillion, one hundred one billion, two hundred twenty-two million, one hundred one thousand, two hundred twenty".