645504405546 has 128 divisors (see below), whose sum is σ = 1734567561216. Its totient is φ = 154660481280.

The previous prime is 645504405527. The next prime is 645504405547.

It is a happy number.

645504405546 is nontrivially palindromic in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 645504405495 and 645504405504.

It is not an unprimeable number, because it can be changed into a prime (645504405547) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 8930965 + ... + 9002951.

It is an arithmetic number, because the mean of its divisors is an integer number (13551309072).

Almost surely, 2^645504405546 is an apocalyptic number.

645504405546 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 645504405546, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (867283780608).

645504405546 is an abundant number, since it is smaller than the sum of its proper divisors (1089063155670).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

645504405546 is a wasteful number, since it uses less digits than its factorization.

645504405546 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 73516.

The product of its (nonzero) digits is 5760000, while the sum is 48.

The spelling of 645504405546 in words is "six hundred forty-five billion, five hundred four million, four hundred five thousand, five hundred forty-six".