561739 has 4 divisors (see below), whose sum is σ = 571320. Its totient is φ = 552160.

The previous prime is 561733. The next prime is 561761. The reversal of 561739 is 937165.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 937165 = 5 ⋅187433.

It is a cyclic number.

It is not a de Polignac number, because 561739 - 2¹⁵ = 528971 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 561739.

It is not an unprimeable number, because it can be changed into a prime (561733) 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, 4702 + ... + 4819.

It is an arithmetic number, because the mean of its divisors is an integer number (142830).

2⁵⁶¹⁷³⁹ is an apocalyptic number.

561739 is a gapful number since it is divisible by the number (59) formed by its first and last digit.

561739 is a deficient number, since it is larger than the sum of its proper divisors (9581).

561739 is an equidigital number, since it uses as much as digits as its factorization.

561739 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9580.

The product of its digits is 5670, while the sum is 31.

The square root of 561739 is about 749.4924949591. The cubic root of 561739 is about 82.5109382497.

The spelling of 561739 in words is "five hundred sixty-one thousand, seven hundred thirty-nine".