665555555566 has 32 divisors (see below), whose sum is σ = 1164572523360. Its totient is φ = 281910528000.

The previous prime is 665555555557. The next prime is 665555555627.

665555555566 is nontrivially palindromic in base 10.

It is a zygodrome in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 665555555498 and 665555555507.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8771931 + ... + 8847478.

It is an arithmetic number, because the mean of its divisors is an integer number (36392891355).

Almost surely, 2^665555555566 is an apocalyptic number.

665555555566 is a deficient number, since it is larger than the sum of its proper divisors (499016967794).

665555555566 is a wasteful number, since it uses less digits than its factorization.

665555555566 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17619540.

The product of its digits is 506250000, while the sum is 64.

The spelling of 665555555566 in words is "six hundred sixty-five billion, five hundred fifty-five million, five hundred fifty-five thousand, five hundred sixty-six".