561819 has 4 divisors (see below), whose sum is σ = 749096. Its totient is φ = 374544.

The previous prime is 561809. The next prime is 561829. The reversal of 561819 is 918165.

It is a happy number.

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

It is an interprime number because it is at equal distance from previous prime (561809) and next prime (561829).

It is not a de Polignac number, because 561819 - 2⁵ = 561787 is a prime.

It is a super-2 number, since 2×561819² = 631281177522, which contains 22 as substring.

It is a D-number.

It is a Duffinian number.

561819 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (561809) 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, 93634 + ... + 93639.

It is an arithmetic number, because the mean of its divisors is an integer number (187274).

2⁵⁶¹⁸¹⁹ is an apocalyptic number.

561819 is a deficient number, since it is larger than the sum of its proper divisors (187277).

561819 is a wasteful number, since it uses less digits than its factorization.

561819 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 187276.

The product of its digits is 2160, while the sum is 30.

The square root of 561819 is about 749.5458625061. The cubic root of 561819 is about 82.5148549926.

The spelling of 561819 in words is "five hundred sixty-one thousand, eight hundred nineteen".