21306550123 has 2 divisors, whose sum is σ = 21306550124. Its totient is φ = 21306550122.

The previous prime is 21306550061. The next prime is 21306550141. The reversal of 21306550123 is 32105560312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21306550123 - 2¹⁷ = 21306419051 is a prime.

It is a super-2 number, since 2×21306550123² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21306550091 and 21306550100.

It is not a weakly prime, because it can be changed into another prime (21306553123) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10653275061 + 10653275062.

It is an arithmetic number, because the mean of its divisors is an integer number (10653275062).

Almost surely, 2^21306550123 is an apocalyptic number.

21306550123 is a deficient number, since it is larger than the sum of its proper divisors (1).

21306550123 is an equidigital number, since it uses as much as digits as its factorization.

21306550123 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5400, while the sum is 28.

The spelling of 21306550123 in words is "twenty-one billion, three hundred six million, five hundred fifty thousand, one hundred twenty-three".