21500231645111 has 2 divisors, whose sum is σ = 21500231645112. Its totient is φ = 21500231645110.

The previous prime is 21500231645099. The next prime is 21500231645117. The reversal of 21500231645111 is 11154613200512.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21500231645111 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21500231645117) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10750115822555 + 10750115822556.

It is an arithmetic number, because the mean of its divisors is an integer number (10750115822556).

Almost surely, 2^{21500231645111} is an apocalyptic number.

21500231645111 is a deficient number, since it is larger than the sum of its proper divisors (1).

21500231645111 is an equidigital number, since it uses as much as digits as its factorization.

21500231645111 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7200, while the sum is 32.

Adding to 21500231645111 its reverse (11154613200512), we get a palindrome (32654844845623).

The spelling of 21500231645111 in words is "twenty-one trillion, five hundred billion, two hundred thirty-one million, six hundred forty-five thousand, one hundred eleven".