21121110100000 has 144 divisors (see below), whose sum is σ = 52151864707656. Its totient is φ = 8419598080000.

The previous prime is 21121110099983. The next prime is 21121110100001. The reversal of 21121110100000 is 101112112.

It can be written as a sum of positive squares in 12 ways, for example, as 10171073180944 + 10950036919056 = 3189212^2 + 3309084^2 .

It is a super-2 number, since 2×21121110100000² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is a self number, because there is not a number n which added to its sum of digits gives 21121110100000.

It is not an unprimeable number, because it can be changed into a prime (21121110100001) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 28939572 + ... + 29660428.

Almost surely, 2^{21121110100000} is an apocalyptic number.

21121110100000 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 21121110100000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26075932353828).

21121110100000 is an abundant number, since it is smaller than the sum of its proper divisors (31030754607656).

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

21121110100000 is an frugal number, since it uses more digits than its factorization.

21121110100000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 721185 (or 721157 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 10.

Adding to 21121110100000 its reverse (101112112), we get a palindrome (21121211212112).

The spelling of 21121110100000 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred ten million, one hundred thousand".