561638 has 24 divisors (see below), whose sum is σ = 1071144. Its totient is φ = 218400.

The previous prime is 561607. The next prime is 561667. The reversal of 561638 is 836165.

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

It is a self number, because there is not a number n which added to its sum of digits gives 561638.

It is a congruent number.

It is an unprimeable number.

561638 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 818 + ... + 1338.

It is an arithmetic number, because the mean of its divisors is an integer number (44631).

2⁵⁶¹⁶³⁸ is an apocalyptic number.

561638 is a deficient number, since it is larger than the sum of its proper divisors (509506).

561638 is a wasteful number, since it uses less digits than its factorization.

561638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 548 (or 541 counting only the distinct ones).

The product of its digits is 4320, while the sum is 29.

The square root of 561638 is about 749.4251130033. The cubic root of 561638 is about 82.5059928307.

The spelling of 561638 in words is "five hundred sixty-one thousand, six hundred thirty-eight".