21211100001101 has 4 divisors (see below), whose sum is σ = 21216818823900. Its totient is φ = 21205381178304.

The previous prime is 21211100001097. The next prime is 21211100001103. The reversal of 21211100001101 is 10110000111212.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3810104898601 + 17400995102500 = 1951949^2 + 4171450^2 .

It is a cyclic number.

It is not a de Polignac number, because 21211100001101 - 2² = 21211100001097 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211100001103) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2859405836 + ... + 2859413253.

It is an arithmetic number, because the mean of its divisors is an integer number (5304204705975).

Almost surely, 2^{21211100001101} is an apocalyptic number.

It is an amenable number.

21211100001101 is a deficient number, since it is larger than the sum of its proper divisors (5718822799).

21211100001101 is an equidigital number, since it uses as much as digits as its factorization.

21211100001101 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5718822798.

The product of its (nonzero) digits is 4, while the sum is 11.

Adding to 21211100001101 its reverse (10110000111212), we get a palindrome (31321100112313).

The spelling of 21211100001101 in words is "twenty-one trillion, two hundred eleven billion, one hundred million, one thousand, one hundred one".