66656543 has 2 divisors, whose sum is σ = 66656544. Its totient is φ = 66656542.

The previous prime is 66656533. The next prime is 66656549. The reversal of 66656543 is 34565666.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66656543 - 2¹² = 66652447 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 66656543.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66656549) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33328271 + 33328272.

It is an arithmetic number, because the mean of its divisors is an integer number (33328272).

Almost surely, 2^66656543 is an apocalyptic number.

66656543 is a deficient number, since it is larger than the sum of its proper divisors (1).

66656543 is an equidigital number, since it uses as much as digits as its factorization.

66656543 is an evil number, because the sum of its binary digits is even.

The product of its digits is 388800, while the sum is 41.

The square root of 66656543 is about 8164.3458402985. The cubic root of 66656543 is about 405.4596072707.

The spelling of 66656543 in words is "sixty-six million, six hundred fifty-six thousand, five hundred forty-three".