21115323256123 has 2 divisors, whose sum is σ = 21115323256124. Its totient is φ = 21115323256122.

The previous prime is 21115323256117. The next prime is 21115323256151. The reversal of 21115323256123 is 32165232351112.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21115323256123 - 2⁴¹ = 18916300000571 is a prime.

It is a super-2 number, since 2×21115323256123² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21115323256103) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10557661628061 + 10557661628062.

It is an arithmetic number, because the mean of its divisors is an integer number (10557661628062).

Almost surely, 2^{21115323256123} is an apocalyptic number.

21115323256123 is a deficient number, since it is larger than the sum of its proper divisors (1).

21115323256123 is an equidigital number, since it uses as much as digits as its factorization.

21115323256123 is an evil number, because the sum of its binary digits is even.

The product of its digits is 64800, while the sum is 37.

The spelling of 21115323256123 in words is "twenty-one trillion, one hundred fifteen billion, three hundred twenty-three million, two hundred fifty-six thousand, one hundred twenty-three".