709666 has 4 divisors (see below), whose sum is σ = 1064502. Its totient is φ = 354832.

The previous prime is 709663. The next prime is 709673. The reversal of 709666 is 666907.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 666907 = 251 ⋅2657.

It can be written as a sum of positive squares in only one way, i.e., 525625 + 184041 = 725^2 + 429^2 .

It is not an unprimeable number, because it can be changed into a prime (709663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 177415 + ... + 177418.

2⁷⁰⁹⁶⁶⁶ is an apocalyptic number.

709666 is a deficient number, since it is larger than the sum of its proper divisors (354836).

709666 is a wasteful number, since it uses less digits than its factorization.

709666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 354835.

The product of its (nonzero) digits is 13608, while the sum is 34.

The square root of 709666 is about 842.4167614667. The cubic root of 709666 is about 89.1972228619.

The spelling of 709666 in words is "seven hundred nine thousand, six hundred sixty-six".