21000331111 has 4 divisors (see below), whose sum is σ = 21074537512. Its totient is φ = 20926124712.

The previous prime is 21000331061. The next prime is 21000331117. The reversal of 21000331111 is 11113300012.

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 21000331111 - 2¹⁵ = 21000298343 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21000331091 and 21000331100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000331117) 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 3 ways as a sum of consecutive naturals, for example, 37102776 + ... + 37103341.

It is an arithmetic number, because the mean of its divisors is an integer number (5268634378).

Almost surely, 2^21000331111 is an apocalyptic number.

21000331111 is a deficient number, since it is larger than the sum of its proper divisors (74206401).

21000331111 is an equidigital number, since it uses as much as digits as its factorization.

21000331111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 74206400.

The product of its (nonzero) digits is 18, while the sum is 13.

Adding to 21000331111 its reverse (11113300012), we get a palindrome (32113631123).

The spelling of 21000331111 in words is "twenty-one billion, three hundred thirty-one thousand, one hundred eleven".