646566665646 has 32 divisors (see below), whose sum is σ = 1410851385216. Its totient is φ = 195907004000.

The previous prime is 646566665579. The next prime is 646566665683.

646566665646 is nontrivially palindromic in base 10.

It is a Harshad number since it is a multiple of its sum of digits (66).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 32041 + ... + 1137611.

It is an arithmetic number, because the mean of its divisors is an integer number (44089105788).

Almost surely, 2^646566665646 is an apocalyptic number.

646566665646 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

646566665646 is an abundant number, since it is smaller than the sum of its proper divisors (764284719570).

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

646566665646 is a wasteful number, since it uses less digits than its factorization.

646566665646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1114448.

The product of its digits is 671846400, while the sum is 66.

The spelling of 646566665646 in words is "six hundred forty-six billion, five hundred sixty-six million, six hundred sixty-five thousand, six hundred forty-six".