613661 has 2 divisors, whose sum is σ = 613662. Its totient is φ = 613660.

The previous prime is 613651. The next prime is 613667. The reversal of 613661 is 166316.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 504100 + 109561 = 710^2 + 331^2 .

It is a cyclic number.

It is not a de Polignac number, because 613661 - 2⁶ = 613597 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (613667) 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 as a sum of consecutive naturals, namely, 306830 + 306831.

It is an arithmetic number, because the mean of its divisors is an integer number (306831).

2⁶¹³⁶⁶¹ is an apocalyptic number.

It is an amenable number.

613661 is a deficient number, since it is larger than the sum of its proper divisors (1).

613661 is an equidigital number, since it uses as much as digits as its factorization.

613661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 648, while the sum is 23.

The square root of 613661 is about 783.3651766577. The cubic root of 613661 is about 84.9785874553.

Adding to 613661 its reverse (166316), we get a palindrome (779977).

The spelling of 613661 in words is "six hundred thirteen thousand, six hundred sixty-one".