645664466546 has 64 divisors (see below), whose sum is σ = 1153047985920. Its totient is φ = 267864576000.

The previous prime is 645664466543. The next prime is 645664466609.

645664466546 is nontrivially palindromic in base 10.

645664466546 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Smith number, since the sum of its digits (62) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (645664466543) 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, 1420490 + ... + 1819098.

It is an arithmetic number, because the mean of its divisors is an integer number (18016374780).

Almost surely, 2^645664466546 is an apocalyptic number.

645664466546 is a deficient number, since it is larger than the sum of its proper divisors (507383519374).

645664466546 is a wasteful number, since it uses less digits than its factorization.

645664466546 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 398771.

The product of its digits is 298598400, while the sum is 62.

The spelling of 645664466546 in words is "six hundred forty-five billion, six hundred sixty-four million, four hundred sixty-six thousand, five hundred forty-six".