6661668 has 24 divisors (see below), whose sum is σ = 16739968. Its totient is φ = 2049696.

The previous prime is 6661661. The next prime is 6661687. The reversal of 6661668 is 8661666.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is not an unprimeable number, because it can be changed into a prime (6661661) 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, 21196 + ... + 21507.

Almost surely, 2^6661668 is an apocalyptic number.

It is an amenable number.

6661668 is an abundant number, since it is smaller than the sum of its proper divisors (10078300).

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

6661668 is a wasteful number, since it uses less digits than its factorization.

6661668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42723 (or 42721 counting only the distinct ones).

The product of its digits is 62208, while the sum is 39.

The square root of 6661668 is about 2581.0207283166. The cubic root of 6661668 is about 188.1601547603.

The spelling of 6661668 in words is "six million, six hundred sixty-one thousand, six hundred sixty-eight".