561778361 has 2 divisors, whose sum is σ = 561778362. Its totient is φ = 561778360.

The previous prime is 561778337. The next prime is 561778387. The reversal of 561778361 is 163877165.

561778361 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 462895225 + 98883136 = 21515^2 + 9944^2 .

It is a cyclic number.

It is not a de Polignac number, because 561778361 - 2⁶ = 561778297 is a prime.

It is not a weakly prime, because it can be changed into another prime (561778331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 280889180 + 280889181.

It is an arithmetic number, because the mean of its divisors is an integer number (280889181).

Almost surely, 2^561778361 is an apocalyptic number.

It is an amenable number.

561778361 is a deficient number, since it is larger than the sum of its proper divisors (1).

561778361 is an equidigital number, since it uses as much as digits as its factorization.

561778361 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 211680, while the sum is 44.

The square root of 561778361 is about 23701.8640828100. The cubic root of 561778361 is about 825.1286538266.

The spelling of 561778361 in words is "five hundred sixty-one million, seven hundred seventy-eight thousand, three hundred sixty-one".