21113111 has 2 divisors, whose sum is σ = 21113112. Its totient is φ = 21113110.

The previous prime is 21113101. The next prime is 21113119. The reversal of 21113111 is 11131112.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21113111 - 2¹⁸ = 20850967 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21113092 and 21113101.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21113119) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10556555 + 10556556.

It is an arithmetic number, because the mean of its divisors is an integer number (10556556).

Almost surely, 2^21113111 is an apocalyptic number.

21113111 is a deficient number, since it is larger than the sum of its proper divisors (1).

21113111 is an equidigital number, since it uses as much as digits as its factorization.

21113111 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6, while the sum is 11.

The square root of 21113111 is about 4594.9005429933. The cubic root of 21113111 is about 276.3868716988.

Adding to 21113111 its reverse (11131112), we get a palindrome (32244223).

It can be divided in two parts, 2 and 1113111, that multiplied together give a palindrome (2226222).

The spelling of 21113111 in words is "twenty-one million, one hundred thirteen thousand, one hundred eleven".