561657 has 4 divisors (see below), whose sum is σ = 748880. Its totient is φ = 374436.

The previous prime is 561607. The next prime is 561667. The reversal of 561657 is 756165.

561657 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 561657 - 2⁷ = 561529 is a prime.

It is a D-number.

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 561657.

It is not an unprimeable number, because it can be changed into a prime (561607) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 93607 + ... + 93612.

It is an arithmetic number, because the mean of its divisors is an integer number (187220).

2⁵⁶¹⁶⁵⁷ is an apocalyptic number.

It is an amenable number.

561657 is a deficient number, since it is larger than the sum of its proper divisors (187223).

561657 is a wasteful number, since it uses less digits than its factorization.

561657 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 187222.

The product of its digits is 6300, while the sum is 30.

The square root of 561657 is about 749.4377892794. The cubic root of 561657 is about 82.5069232023.

The spelling of 561657 in words is "five hundred sixty-one thousand, six hundred fifty-seven".