561511 has 4 divisors (see below), whose sum is σ = 563152. Its totient is φ = 559872.

The previous prime is 561461. The next prime is 561521. The reversal of 561511 is 115165.

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

It is a 8-Lehmer number, since φ(561511) divides (561511-1)⁸.

It is a cyclic number.

It is not a de Polignac number, because 561511 - 2¹⁹ = 37223 is a prime.

It is a Duffinian number.

561511 is a lucky number.

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 90 + ... + 1063.

It is an arithmetic number, because the mean of its divisors is an integer number (140788).

2⁵⁶¹⁵¹¹ is an apocalyptic number.

561511 is a deficient number, since it is larger than the sum of its proper divisors (1641).

561511 is a wasteful number, since it uses less digits than its factorization.

561511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1640.

The product of its digits is 150, while the sum is 19.

The square root of 561511 is about 749.3403765980. The cubic root of 561511 is about 82.4997734919.

Adding to 561511 its reverse (115165), we get a palindrome (676676).

It can be divided in two parts, 5 and 61511, that added together give a palindrome (61516).

The spelling of 561511 in words is "five hundred sixty-one thousand, five hundred eleven".