21606642431123 has 2 divisors, whose sum is σ = 21606642431124. Its totient is φ = 21606642431122.

The previous prime is 21606642431069. The next prime is 21606642431137. The reversal of 21606642431123 is 32113424660612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21606642431123 - 2¹⁰ = 21606642430099 is a prime.

It is a super-2 number, since 2×21606642431123² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21606642431183) 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 as a sum of consecutive naturals, namely, 10803321215561 + 10803321215562.

It is an arithmetic number, because the mean of its divisors is an integer number (10803321215562).

Almost surely, 2^{21606642431123} is an apocalyptic number.

21606642431123 is a deficient number, since it is larger than the sum of its proper divisors (1).

21606642431123 is an equidigital number, since it uses as much as digits as its factorization.

21606642431123 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 248832, while the sum is 41.

The spelling of 21606642431123 in words is "twenty-one trillion, six hundred six billion, six hundred forty-two million, four hundred thirty-one thousand, one hundred twenty-three".