6666558556666 has 4 divisors (see below), whose sum is σ = 9999837835002. Its totient is φ = 3333279278332.

The previous prime is 6666558556633. The next prime is 6666558556681.

6666558556666 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 4846069501641 + 1820489055025 = 2201379^2 + 1349255^2 .

It is a super-2 number, since 2×6666558556666² (a number of 26 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 6666558556592 and 6666558556601.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1666639639165 + ... + 1666639639168.

Almost surely, 2^{6666558556666} is an apocalyptic number.

6666558556666 is a deficient number, since it is larger than the sum of its proper divisors (3333279278336).

6666558556666 is a wasteful number, since it uses less digits than its factorization.

6666558556666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3333279278335.

The product of its digits is 8398080000, while the sum is 76.

The spelling of 6666558556666 in words is "six trillion, six hundred sixty-six billion, five hundred fifty-eight million, five hundred fifty-six thousand, six hundred sixty-six".