561089781 has 24 divisors (see below), whose sum is σ = 950544960. Its totient is φ = 320436648.

The previous prime is 561089701. The next prime is 561089803. The reversal of 561089781 is 187980165.

561089781 is a `hidden beast` number, since 561 + 0 + 8 + 9 + 7 + 81 = 666.

561089781 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 561089781 - 2²³ = 552701173 is a prime.

It is a super-2 number, since 2×561089781² = 629643484685255922, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (561089701) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 324786 + ... + 326508.

It is an arithmetic number, because the mean of its divisors is an integer number (39606040).

Almost surely, 2^561089781 is an apocalyptic number.

It is an amenable number.

561089781 is a deficient number, since it is larger than the sum of its proper divisors (389455179).

561089781 is an frugal number, since it uses more digits than its factorization.

561089781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3462 (or 1733 counting only the distinct ones).

The product of its (nonzero) digits is 120960, while the sum is 45.

The square root of 561089781 is about 23687.3337672267. Note that the first 3 decimals coincide. The cubic root of 561089781 is about 824.7913918842.

The spelling of 561089781 in words is "five hundred sixty-one million, eighty-nine thousand, seven hundred eighty-one".