665349943566 has 64 divisors (see below), whose sum is σ = 1694353489920. Its totient is φ = 169141179360.

The previous prime is 665349943561. The next prime is 665349943603.

665349943566 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 junction number, because it is equal to n+sod(n) for n = 665349943497 and 665349943506.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665349943561) 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, 15299046 + ... + 15342473.

It is an arithmetic number, because the mean of its divisors is an integer number (26474273280).

Almost surely, 2^665349943566 is an apocalyptic number.

665349943566 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

665349943566 is an abundant number, since it is smaller than the sum of its proper divisors (1029003546354).

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

665349943566 is a wasteful number, since it uses less digits than its factorization.

665349943566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30641589.

The product of its digits is 377913600, while the sum is 66.

The spelling of 665349943566 in words is "six hundred sixty-five billion, three hundred forty-nine million, nine hundred forty-three thousand, five hundred sixty-six".