6556666 has 4 divisors (see below), whose sum is σ = 9835002. Its totient is φ = 3278332.

The previous prime is 6556657. The next prime is 6556673. The reversal of 6556666 is 6666556.

It is a happy number.

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., 5784025 + 772641 = 2405^2 + 879^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1639165 + ... + 1639168.

Almost surely, 2^6556666 is an apocalyptic number.

6556666 is a deficient number, since it is larger than the sum of its proper divisors (3278336).

6556666 is a wasteful number, since it uses less digits than its factorization.

6556666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3278335.

The product of its digits is 194400, while the sum is 40.

The square root of 6556666 is about 2560.5987581033. The cubic root of 6556666 is about 187.1663137635.

The spelling of 6556666 in words is "six million, five hundred fifty-six thousand, six hundred sixty-six".