666738 has 16 divisors (see below), whose sum is σ = 1481760. Its totient is φ = 222228.

The previous prime is 666737. The next prime is 666749. The reversal of 666738 is 837666.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (666733) 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, 6120 + ... + 6227.

It is an arithmetic number, because the mean of its divisors is an integer number (92610).

2⁶⁶⁶⁷³⁸ is an apocalyptic number.

666738 is an abundant number, since it is smaller than the sum of its proper divisors (815022).

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

666738 is a wasteful number, since it uses less digits than its factorization.

666738 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12358 (or 12352 counting only the distinct ones).

The product of its digits is 36288, while the sum is 36.

The square root of 666738 is about 816.5402623264. The cubic root of 666738 is about 87.3611621328.

The spelling of 666738 in words is "six hundred sixty-six thousand, seven hundred thirty-eight".