664416505 has 4 divisors (see below), whose sum is σ = 797299812. Its totient is φ = 531533200.

The previous prime is 664416503. The next prime is 664416517. The reversal of 664416505 is 505614466.

664416505 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

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 339443776 + 324972729 = 18424^2 + 18027^2 .

It is not a de Polignac number, because 664416505 - 2¹ = 664416503 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (664416503) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 66441646 + ... + 66441655.

It is an arithmetic number, because the mean of its divisors is an integer number (199324953).

Almost surely, 2^664416505 is an apocalyptic number.

It is an amenable number.

664416505 is a deficient number, since it is larger than the sum of its proper divisors (132883307).

664416505 is a wasteful number, since it uses less digits than its factorization.

664416505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132883306.

The product of its (nonzero) digits is 86400, while the sum is 37.

The square root of 664416505 is about 25776.2779508602. The cubic root of 664416505 is about 872.5965082367.

The spelling of 664416505 in words is "six hundred sixty-four million, four hundred sixteen thousand, five hundred five".