561618 has 24 divisors (see below), whose sum is σ = 1248156. Its totient is φ = 182400.

The previous prime is 561607. The next prime is 561667. The reversal of 561618 is 816165.

It can be written as a sum of positive squares in 2 ways, for example, as 356409 + 205209 = 597^2 + 453^2 .

It is a Smith number, since the sum of its digits (27) coincides with the sum of the digits of its prime factors.

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

It is a junction number, because it is equal to n+sod(n) for n = 561591 and 561600.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 358 + ... + 1118.

2⁵⁶¹⁶¹⁸ is an apocalyptic number.

561618 is an abundant number, since it is smaller than the sum of its proper divisors (686538).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

561618 is a wasteful number, since it uses less digits than its factorization.

561618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 810 (or 807 counting only the distinct ones).

The product of its digits is 1440, while the sum is 27.

The square root of 561618 is about 749.4117693231. The cubic root of 561618 is about 82.5050134694.

It can be divided in two parts, 56161 and 8, that added together give a square (56169 = 237²).

The spelling of 561618 in words is "five hundred sixty-one thousand, six hundred eighteen".