21201111200021 has 8 divisors (see below), whose sum is σ = 21275727932760. Its totient is φ = 21126509828352.

The previous prime is 21201111199991. The next prime is 21201111200033. The reversal of 21201111200021 is 12000211110212.

It can be written as a sum of positive squares in 4 ways, for example, as 7833203073796 + 13367908126225 = 2798786^2 + 3656215^2 .

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21201111200021 is a prime.

It is a super-2 number, since 2×21201111200021² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21201111199969 and 21201111200005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201111200921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1071536 + ... + 6599273.

It is an arithmetic number, because the mean of its divisors is an integer number (2659465991595).

Almost surely, 2^{21201111200021} is an apocalyptic number.

It is an amenable number.

21201111200021 is a deficient number, since it is larger than the sum of its proper divisors (74616732739).

21201111200021 is an equidigital number, since it uses as much as digits as its factorization.

21201111200021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7680535.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21201111200021 its reverse (12000211110212), we get a palindrome (33201322310233).

The spelling of 21201111200021 in words is "twenty-one trillion, two hundred one billion, one hundred eleven million, two hundred thousand, twenty-one".