215666123 has 2 divisors, whose sum is σ = 215666124. Its totient is φ = 215666122.

The previous prime is 215666119. The next prime is 215666141. The reversal of 215666123 is 321666512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 215666123 - 2² = 215666119 is a prime.

It is a super-2 number, since 2×215666123² = 93023753219702258, which contains 22 as substring.

It is equal to p_11897015 and since 215666123 and 11897015 have the same sum of digits, it is a Honaker prime.

It is a self number, because there is not a number n which added to its sum of digits gives 215666123.

It is not a weakly prime, because it can be changed into another prime (215666153) 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, 107833061 + 107833062.

It is an arithmetic number, because the mean of its divisors is an integer number (107833062).

Almost surely, 2^215666123 is an apocalyptic number.

215666123 is a deficient number, since it is larger than the sum of its proper divisors (1).

215666123 is an equidigital number, since it uses as much as digits as its factorization.

215666123 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12960, while the sum is 32.

The square root of 215666123 is about 14685.5753377251. The cubic root of 215666123 is about 599.6906952079.

The spelling of 215666123 in words is "two hundred fifteen million, six hundred sixty-six thousand, one hundred twenty-three".