661706 has 4 divisors (see below), whose sum is σ = 992562. Its totient is φ = 330852.

The previous prime is 661697. The next prime is 661721. The reversal of 661706 is 607166.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 654481 + 7225 = 809^2 + 85^2 .

It is an unprimeable number.

661706 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 165425 + ... + 165428.

2⁶⁶¹⁷⁰⁶ is an apocalyptic number.

661706 is a deficient number, since it is larger than the sum of its proper divisors (330856).

661706 is a wasteful number, since it uses less digits than its factorization.

661706 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 330855.

The product of its (nonzero) digits is 1512, while the sum is 26.

The square root of 661706 is about 813.4531332535. The cubic root of 661706 is about 87.1408297349.

The spelling of 661706 in words is "six hundred sixty-one thousand, seven hundred six".