666666826 has 16 divisors (see below), whose sum is σ = 1150531200. Its totient is φ = 283795920.

The previous prime is 666666821. The next prime is 666666827. The reversal of 666666826 is 628666666.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (666666821) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 157710 + ... + 161881.

It is an arithmetic number, because the mean of its divisors is an integer number (71908200).

Almost surely, 2^666666826 is an apocalyptic number.

666666826 is a deficient number, since it is larger than the sum of its proper divisors (483864374).

666666826 is a wasteful number, since it uses less digits than its factorization.

666666826 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 319749.

The product of its digits is 4478976, while the sum is 52.

The square root of 666666826 is about 25819.8920601927. The cubic root of 666666826 is about 873.5805343315.

The spelling of 666666826 in words is "six hundred sixty-six million, six hundred sixty-six thousand, eight hundred twenty-six".