66555567 has 16 divisors (see below), whose sum is σ = 106186080. Its totient is φ = 40957056.

The previous prime is 66555553. The next prime is 66555581. The reversal of 66555567 is 76555566.

It is an interprime number because it is at equal distance from previous prime (66555553) and next prime (66555581).

It is not a de Polignac number, because 66555567 - 2⁸ = 66555311 is a prime.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66555967) 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 in 15 ways as a sum of consecutive naturals, for example, 94458 + ... + 95159.

It is an arithmetic number, because the mean of its divisors is an integer number (6636630).

Almost surely, 2^66555567 is an apocalyptic number.

66555567 is a deficient number, since it is larger than the sum of its proper divisors (39630513).

66555567 is a wasteful number, since it uses less digits than its factorization.

66555567 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 189639 (or 189633 counting only the distinct ones).

The product of its digits is 945000, while the sum is 45.

The square root of 66555567 is about 8158.1595350912. The cubic root of 66555567 is about 405.2547642617.

Subtracting 66555567 from its reverse (76555566), we obtain a palindrome (9999999).

The spelling of 66555567 in words is "sixty-six million, five hundred fifty-five thousand, five hundred sixty-seven".