66665775 has 48 divisors (see below), whose sum is σ = 126599040. Its totient is φ = 30614400.

The previous prime is 66665761. The next prime is 66665777. The reversal of 66665775 is 57756666.

It is not a de Polignac number, because 66665775 - 2⁴ = 66665759 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66665777) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 13549 + ... + 17801.

It is an arithmetic number, because the mean of its divisors is an integer number (2637480).

Almost surely, 2^66665775 is an apocalyptic number.

66665775 is a deficient number, since it is larger than the sum of its proper divisors (59933265).

66665775 is a wasteful number, since it uses less digits than its factorization.

66665775 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4296 (or 4291 counting only the distinct ones).

The product of its digits is 1587600, while the sum is 48.

The square root of 66665775 is about 8164.9112058858. The cubic root of 66665775 is about 405.4783252646.

The spelling of 66665775 in words is "sixty-six million, six hundred sixty-five thousand, seven hundred seventy-five".