645866668546 has 16 divisors (see below), whose sum is σ = 1102823719488. Its totient is φ = 280811594800.

The previous prime is 645866668543. The next prime is 645866668561.

645866668546 is nontrivially palindromic in base 10.

It is not an unprimeable number, because it can be changed into a prime (645866668543) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 638207665 + ... + 638208676.

It is an arithmetic number, because the mean of its divisors is an integer number (68926482468).

Almost surely, 2^645866668546 is an apocalyptic number.

645866668546 is a deficient number, since it is larger than the sum of its proper divisors (456957050942).

645866668546 is a wasteful number, since it uses less digits than its factorization.

645866668546 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1276416377.

The product of its digits is 1194393600, while the sum is 70.

The spelling of 645866668546 in words is "six hundred forty-five billion, eight hundred sixty-six million, six hundred sixty-eight thousand, five hundred forty-six".