6921668 has 12 divisors (see below), whose sum is σ = 13044780. Its totient is φ = 3194592.

The previous prime is 6921653. The next prime is 6921671. The reversal of 6921668 is 8661296.

It can be written as a sum of positive squares in 2 ways, for example, as 2849344 + 4072324 = 1688^2 + 2018^2 .

It is a congruent number.

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, 66503 + ... + 66606.

It is an arithmetic number, because the mean of its divisors is an integer number (1087065).

Almost surely, 2^6921668 is an apocalyptic number.

It is an amenable number.

6921668 is a deficient number, since it is larger than the sum of its proper divisors (6123112).

6921668 is a wasteful number, since it uses less digits than its factorization.

6921668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 133126 (or 133124 counting only the distinct ones).

The product of its digits is 31104, while the sum is 38.

The square root of 6921668 is about 2630.9063077198. The cubic root of 6921668 is about 190.5768984787.

The spelling of 6921668 in words is "six million, nine hundred twenty-one thousand, six hundred sixty-eight".