6621666 has 8 divisors (see below), whose sum is σ = 13243344. Its totient is φ = 2207220.

The previous prime is 6621649. The next prime is 6621691. The reversal of 6621666 is 6661266.

It is a sphenic number, since it is the product of 3 distinct primes.

6621666 is an admirable number.

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 551800 + ... + 551811.

It is an arithmetic number, because the mean of its divisors is an integer number (1655418).

Almost surely, 2^6621666 is an apocalyptic number.

6621666 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

6621666 is a wasteful number, since it uses less digits than its factorization.

6621666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1103616.

The product of its digits is 15552, while the sum is 33.

The square root of 6621666 is about 2573.2598003311. The cubic root of 6621666 is about 187.7827768731.

The spelling of 6621666 in words is "six million, six hundred twenty-one thousand, six hundred sixty-six".