863161561 has 6 divisors (see below), whose sum is σ = 884729486. Its totient is φ = 842107200.

The previous prime is 863161547. The next prime is 863161573. The reversal of 863161561 is 165161368.

It can be written as a sum of positive squares in 3 ways, for example, as 98307225 + 764854336 = 9915^2 + 27656^2 .

It is not a de Polignac number, because 863161561 - 2¹⁵ = 863128793 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 863161561.

It is not an unprimeable number, because it can be changed into a prime (863161501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 255060 + ... + 258421.

Almost surely, 2^863161561 is an apocalyptic number.

It is an amenable number.

863161561 is a deficient number, since it is larger than the sum of its proper divisors (21567925).

863161561 is an equidigital number, since it uses as much as digits as its factorization.

863161561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 513563 (or 513522 counting only the distinct ones).

The product of its digits is 25920, while the sum is 37.

The square root of 863161561 is about 29379.6113146515. The cubic root of 863161561 is about 952.1324437494.

The spelling of 863161561 in words is "eight hundred sixty-three million, one hundred sixty-one thousand, five hundred sixty-one".