6661906 has 8 divisors (see below), whose sum is σ = 10010124. Its totient is φ = 3325200.

The previous prime is 6661901. The next prime is 6661933. The reversal of 6661906 is 6091666.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 4995225 + 1666681 = 2235^2 + 1291^2 .

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

It is not an unprimeable number, because it can be changed into a prime (6661901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1245 + ... + 3856.

Almost surely, 2^6661906 is an apocalyptic number.

6661906 is a deficient number, since it is larger than the sum of its proper divisors (3348218).

6661906 is a wasteful number, since it uses less digits than its factorization.

6661906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5756.

The product of its (nonzero) digits is 11664, while the sum is 34.

The square root of 6661906 is about 2581.0668336949. The cubic root of 6661906 is about 188.1623955196.

The spelling of 6661906 in words is "six million, six hundred sixty-one thousand, nine hundred six".