21111000100021 has 8 divisors (see below), whose sum is σ = 22755276757304. Its totient is φ = 19469631096000.

The previous prime is 21111000100013. The next prime is 21111000100051. The reversal of 21111000100021 is 12000100011112.

It can be written as a sum of positive squares in 4 ways, for example, as 2794868429796 + 18316131670225 = 1671786^2 + 4279735^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21111000100021 - 2³ = 21111000100013 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21111000099980 and 21111000100007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21111000100051) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 726898230 + ... + 726927271.

It is an arithmetic number, because the mean of its divisors is an integer number (2844409594663).

Almost surely, 2^{21111000100021} is an apocalyptic number.

It is an amenable number.

21111000100021 is a deficient number, since it is larger than the sum of its proper divisors (1644276657283).

21111000100021 is a wasteful number, since it uses less digits than its factorization.

21111000100021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1453826631.

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

Adding to 21111000100021 its reverse (12000100011112), we get a palindrome (33111100111133).

The spelling of 21111000100021 in words is "twenty-one trillion, one hundred eleven billion, one hundred thousand, twenty-one".