65666505 has 16 divisors (see below), whose sum is σ = 106032960. Its totient is φ = 34699968.

The previous prime is 65666479. The next prime is 65666509. The reversal of 65666505 is 50566656.

It is a happy number.

It is not a de Polignac number, because 65666505 - 2¹⁷ = 65535433 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (65666509) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 18447 + ... + 21716.

It is an arithmetic number, because the mean of its divisors is an integer number (6627060).

Almost surely, 2^65666505 is an apocalyptic number.

It is an amenable number.

65666505 is a deficient number, since it is larger than the sum of its proper divisors (40366455).

65666505 is a wasteful number, since it uses less digits than its factorization.

65666505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40280.

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

The square root of 65666505 is about 8103.4872123056. The cubic root of 65666505 is about 403.4421789580.

It can be divided in two parts, 656 and 66505, that added together give a triangular number (67161 = T₃₆₆).

The spelling of 65666505 in words is "sixty-five million, six hundred sixty-six thousand, five hundred five".