21112220122100 has 144 divisors (see below), whose sum is σ = 49698206204976. Its totient is φ = 7753236480000.

The previous prime is 21112220122073. The next prime is 21112220122129. The reversal of 21112220122100 is 122102221112.

It can be written as a sum of positive squares in 24 ways, for example, as 8321540245264 + 12790679876836 = 2884708^2 + 3576406^2 .

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a congruent number.

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, 690084404 + ... + 690114996.

It is an arithmetic number, because the mean of its divisors is an integer number (345126431979).

Almost surely, 2^{21112220122100} is an apocalyptic number.

21112220122100 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 21112220122100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24849103102488).

21112220122100 is an abundant number, since it is smaller than the sum of its proper divisors (28585986082876).

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

21112220122100 is a wasteful number, since it uses less digits than its factorization.

21112220122100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40566 (or 40559 counting only the distinct ones).

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

Adding to 21112220122100 its reverse (122102221112), we get a palindrome (21234322343212).

The spelling of 21112220122100 in words is "twenty-one trillion, one hundred twelve billion, two hundred twenty million, one hundred twenty-two thousand, one hundred".