666613 has 4 divisors (see below), whose sum is σ = 669708. Its totient is φ = 663520.

The previous prime is 666607. The next prime is 666637. The reversal of 666613 is 316666.

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

It can be written as a sum of positive squares in 2 ways, for example, as 248004 + 418609 = 498^2 + 647^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-666613 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666643) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1198 + ... + 1663.

It is an arithmetic number, because the mean of its divisors is an integer number (167427).

2⁶⁶⁶⁶¹³ is an apocalyptic number.

It is an amenable number.

666613 is a deficient number, since it is larger than the sum of its proper divisors (3095).

666613 is a wasteful number, since it uses less digits than its factorization.

666613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3094.

The product of its digits is 3888, while the sum is 28.

The square root of 666613 is about 816.4637162789. The cubic root of 666613 is about 87.3557023031.

The spelling of 666613 in words is "six hundred sixty-six thousand, six hundred thirteen".