21000100021111 has 4 divisors (see below), whose sum is σ = 21001064544792. Its totient is φ = 20999135497432.

The previous prime is 21000100021093. The next prime is 21000100021127. The reversal of 21000100021111 is 11112000100012.

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

It is a cyclic number.

It is not a de Polignac number, because 21000100021111 - 2²⁹ = 20999563150199 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 (21000100028111) 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, 482229181 + ... + 482272726.

It is an arithmetic number, because the mean of its divisors is an integer number (5250266136198).

Almost surely, 2^{21000100021111} is an apocalyptic number.

21000100021111 is a deficient number, since it is larger than the sum of its proper divisors (964523681).

21000100021111 is an equidigital number, since it uses as much as digits as its factorization.

21000100021111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 964523680.

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

Adding to 21000100021111 its reverse (11112000100012), we get a palindrome (32112100121123).

The spelling of 21000100021111 in words is "twenty-one trillion, one hundred million, twenty-one thousand, one hundred eleven".