664445555 has 4 divisors (see below), whose sum is σ = 797334672. Its totient is φ = 531556440.

The previous prime is 664445543. The next prime is 664445557. The reversal of 664445555 is 555544466.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 555544466 = 2 ⋅277772233.

It is not a de Polignac number, because 664445555 - 2¹⁰ = 664444531 is a prime.

It is a Duffinian number.

It is a zygodrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (664445557) 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, 66444551 + ... + 66444560.

It is an arithmetic number, because the mean of its divisors is an integer number (199333668).

Almost surely, 2^664445555 is an apocalyptic number.

664445555 is a deficient number, since it is larger than the sum of its proper divisors (132889117).

664445555 is a wasteful number, since it uses less digits than its factorization.

664445555 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132889116.

The product of its digits is 1440000, while the sum is 44.

The square root of 664445555 is about 25776.8414473147. The cubic root of 664445555 is about 872.6092254399.

The spelling of 664445555 in words is "six hundred sixty-four million, four hundred forty-five thousand, five hundred fifty-five".