666633505 has 4 divisors (see below), whose sum is σ = 799960212. Its totient is φ = 533306800.

The previous prime is 666633503. The next prime is 666633509. The reversal of 666633505 is 505336666.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 69906321 + 596727184 = 8361^2 + 24428^2 .

It is not a de Polignac number, because 666633505 - 2¹ = 666633503 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (666633503) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66663346 + ... + 66663355.

It is an arithmetic number, because the mean of its divisors is an integer number (199990053).

Almost surely, 2^666633505 is an apocalyptic number.

It is an amenable number.

666633505 is a deficient number, since it is larger than the sum of its proper divisors (133326707).

666633505 is a wasteful number, since it uses less digits than its factorization.

666633505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133326706.

The product of its (nonzero) digits is 291600, while the sum is 40.

The square root of 666633505 is about 25819.2467938164. The cubic root of 666633505 is about 873.5659798040.

The spelling of 666633505 in words is "six hundred sixty-six million, six hundred thirty-three thousand, five hundred five".