561139 has 4 divisors (see below), whose sum is σ = 570400. Its totient is φ = 551880.

The previous prime is 561109. The next prime is 561161. The reversal of 561139 is 931165.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-561139 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561109) 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, 4539 + ... + 4660.

It is an arithmetic number, because the mean of its divisors is an integer number (142600).

2⁵⁶¹¹³⁹ is an apocalyptic number.

561139 is a deficient number, since it is larger than the sum of its proper divisors (9261).

561139 is an equidigital number, since it uses as much as digits as its factorization.

561139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9260.

The product of its digits is 810, while the sum is 25.

The square root of 561139 is about 749.0921171658. The cubic root of 561139 is about 82.4815508180.

The spelling of 561139 in words is "five hundred sixty-one thousand, one hundred thirty-nine".