561621 has 16 divisors (see below), whose sum is σ = 806400. Its totient is φ = 346608.

The previous prime is 561607. The next prime is 561667. The reversal of 561621 is 126165.

It is a happy number.

It is not a de Polignac number, because 561621 - 2⁹ = 561109 is a prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 561621.

It is not an unprimeable number, because it can be changed into a prime (561521) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3280 + ... + 3446.

It is an arithmetic number, because the mean of its divisors is an integer number (50400).

2⁵⁶¹⁶²¹ is an apocalyptic number.

It is an amenable number.

561621 is a deficient number, since it is larger than the sum of its proper divisors (244779).

561621 is a wasteful number, since it uses less digits than its factorization.

561621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 248.

The product of its digits is 360, while the sum is 21.

The square root of 561621 is about 749.4137708903. The cubic root of 561621 is about 82.5051603751.

Adding to 561621 its reverse (126165), we get a palindrome (687786).

The spelling of 561621 in words is "five hundred sixty-one thousand, six hundred twenty-one".