66556065 has 32 divisors (see below), whose sum is σ = 108662400. Its totient is φ = 34781184.

The previous prime is 66556057. The next prime is 66556067. The reversal of 66556065 is 56065566.

It is a happy number.

It is not a de Polignac number, because 66556065 - 2³ = 66556057 is a prime.

It is not an unprimeable number, because it can be changed into a prime (66556067) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 216642 + ... + 216948.

It is an arithmetic number, because the mean of its divisors is an integer number (3395700).

Almost surely, 2^66556065 is an apocalyptic number.

It is an amenable number.

66556065 is a deficient number, since it is larger than the sum of its proper divisors (42106335).

66556065 is a wasteful number, since it uses less digits than its factorization.

66556065 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 561.

The product of its (nonzero) digits is 162000, while the sum is 39.

The square root of 66556065 is about 8158.1900566241. The cubic root of 66556065 is about 405.2557750280.

It can be divided in two parts, 6655 and 6065, that added together give a triangular number (12720 = T₁₅₉).

The spelling of 66556065 in words is "sixty-six million, five hundred fifty-six thousand, sixty-five".