561381 has 4 divisors (see below), whose sum is σ = 748512. Its totient is φ = 374252.

The previous prime is 561377. The next prime is 561389. The reversal of 561381 is 183165.

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 a cyclic number.

It is not a de Polignac number, because 561381 - 2² = 561377 is a prime.

It is a super-2 number, since 2×561381² = 630297254322, which contains 22 as substring.

It is a D-number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 561381.

It is not an unprimeable number, because it can be changed into a prime (561389) 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, 93561 + ... + 93566.

It is an arithmetic number, because the mean of its divisors is an integer number (187128).

2⁵⁶¹³⁸¹ is an apocalyptic number.

It is an amenable number.

561381 is a deficient number, since it is larger than the sum of its proper divisors (187131).

561381 is a wasteful number, since it uses less digits than its factorization.

561381 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 187130.

The product of its digits is 720, while the sum is 24.

The square root of 561381 is about 749.2536286198. The cubic root of 561381 is about 82.4934062682.

The spelling of 561381 in words is "five hundred sixty-one thousand, three hundred eighty-one".