21012331111 has 2 divisors, whose sum is σ = 21012331112. Its totient is φ = 21012331110.

The previous prime is 21012331103. The next prime is 21012331133. The reversal of 21012331111 is 11113321012.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21012331111 - 2³ = 21012331103 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21012331181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506165555 + 10506165556.

It is an arithmetic number, because the mean of its divisors is an integer number (10506165556).

Almost surely, 2^21012331111 is an apocalyptic number.

21012331111 is a deficient number, since it is larger than the sum of its proper divisors (1).

21012331111 is an equidigital number, since it uses as much as digits as its factorization.

21012331111 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 36, while the sum is 16.

Adding to 21012331111 its reverse (11113321012), we get a palindrome (32125652123).

The spelling of 21012331111 in words is "twenty-one billion, twelve million, three hundred thirty-one thousand, one hundred eleven".