666506505 has 32 divisors (see below), whose sum is σ = 1290449664. Its totient is φ = 286765056.

The previous prime is 666506461. The next prime is 666506509. The reversal of 666506505 is 505605666.

It is a happy number.

It is not a de Polignac number, because 666506505 - 2⁶ = 666506441 is a prime.

It is not an unprimeable number, because it can be changed into a prime (666506509) 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, 184912 + ... + 188481.

It is an arithmetic number, because the mean of its divisors is an integer number (40326552).

Almost surely, 2^666506505 is an apocalyptic number.

It is an amenable number.

666506505 is a deficient number, since it is larger than the sum of its proper divisors (623943159).

666506505 is a wasteful number, since it uses less digits than its factorization.

666506505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 373425.

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

The square root of 666506505 is about 25816.7872710762. The cubic root of 666506505 is about 873.5105020817.

The spelling of 666506505 in words is "six hundred sixty-six million, five hundred six thousand, five hundred five".