66655999 has 2 divisors, whose sum is σ = 66656000. Its totient is φ = 66655998.

The previous prime is 66655991. The next prime is 66656027. The reversal of 66655999 is 99955666.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66655999 - 2³ = 66655991 is a prime.

It is a zygodrome in base 10.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66655991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33327999 + 33328000.

It is an arithmetic number, because the mean of its divisors is an integer number (33328000).

Almost surely, 2^66655999 is an apocalyptic number.

66655999 is a deficient number, since it is larger than the sum of its proper divisors (1).

66655999 is an equidigital number, since it uses as much as digits as its factorization.

66655999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3936600, while the sum is 55.

The square root of 66655999 is about 8164.3125246404. The cubic root of 66655999 is about 405.4585042500.

It can be divided in two parts, 666 and 55999, that added together give a palindrome (56665).

The spelling of 66655999 in words is "sixty-six million, six hundred fifty-five thousand, nine hundred ninety-nine".