221206123 has 2 divisors, whose sum is σ = 221206124. Its totient is φ = 221206122.

The previous prime is 221206103. The next prime is 221206127. The reversal of 221206123 is 321602122.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 221206123 - 2²⁵ = 187651691 is a prime.

It is a super-2 number, since 2×221206123² = 97864297705382258, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 221206123.

It is not a weakly prime, because it can be changed into another prime (221206127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110603061 + 110603062.

It is an arithmetic number, because the mean of its divisors is an integer number (110603062).

Almost surely, 2^221206123 is an apocalyptic number.

221206123 is a deficient number, since it is larger than the sum of its proper divisors (1).

221206123 is an equidigital number, since it uses as much as digits as its factorization.

221206123 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 221206123 is about 14872.9997982922. Note that the first 3 decimals coincide. The cubic root of 221206123 is about 604.7822662066.

Adding to 221206123 its reverse (321602122), we get a palindrome (542808245).

The spelling of 221206123 in words is "two hundred twenty-one million, two hundred six thousand, one hundred twenty-three".