613561 has 8 divisors (see below), whose sum is σ = 668360. Its totient is φ = 559872.

The previous prime is 613559. The next prime is 613573. The reversal of 613561 is 165316.

It can be written as a sum of positive squares in 4 ways, for example, as 3600 + 609961 = 60^2 + 781^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a 7-Lehmer number, since φ(613561) divides (613561-1)⁷.

It is a cyclic number.

It is not a de Polignac number, because 613561 - 2¹ = 613559 is a prime.

It is a Duffinian number.

613561 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (613061) 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 in 7 ways as a sum of consecutive naturals, for example, 1201 + ... + 1633.

It is an arithmetic number, because the mean of its divisors is an integer number (83545).

2⁶¹³⁵⁶¹ is an apocalyptic number.

It is an amenable number.

613561 is a deficient number, since it is larger than the sum of its proper divisors (54799).

613561 is a wasteful number, since it uses less digits than its factorization.

613561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 555.

The product of its digits is 540, while the sum is 22.

The square root of 613561 is about 783.3013468647. The cubic root of 613561 is about 84.9739712690.

Adding to 613561 its reverse (165316), we get a palindrome (778877).

The spelling of 613561 in words is "six hundred thirteen thousand, five hundred sixty-one".