616561 has 8 divisors (see below), whose sum is σ = 702144. Its totient is φ = 535920.

The previous prime is 616547. The next prime is 616579. The reversal of 616561 is 165616.

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

It is not a de Polignac number, because 616561 - 2⁵ = 616529 is a prime.

It is an alternating number because its digits alternate between even and odd.

616561 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (616501) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 966 + ... + 1471.

It is an arithmetic number, because the mean of its divisors is an integer number (87768).

2⁶¹⁶⁵⁶¹ is an apocalyptic number.

It is an amenable number.

616561 is a deficient number, since it is larger than the sum of its proper divisors (85583).

616561 is a wasteful number, since it uses less digits than its factorization.

616561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2471.

The product of its digits is 1080, while the sum is 25.

The square root of 616561 is about 785.2139835739. The cubic root of 616561 is about 85.1122392703.

It can be divided in two parts, 6165 and 61, that added together give a palindrome (6226).

The spelling of 616561 in words is "six hundred sixteen thousand, five hundred sixty-one".