261161559 has 12 divisors (see below), whose sum is σ = 390241800. Its totient is φ = 168103824.

The previous prime is 261161543. The next prime is 261161567. The reversal of 261161559 is 955161162.

261161559 is a `hidden beast` number, since 26 + 11 + 615 + 5 + 9 = 666.

It is not a de Polignac number, because 261161559 - 2⁴ = 261161543 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261121559) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 500049 + ... + 500570.

It is an arithmetic number, because the mean of its divisors is an integer number (32520150).

Almost surely, 2^261161559 is an apocalyptic number.

261161559 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

261161559 is a deficient number, since it is larger than the sum of its proper divisors (129080241).

261161559 is a wasteful number, since it uses less digits than its factorization.

261161559 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1000654 (or 1000651 counting only the distinct ones).

The product of its digits is 16200, while the sum is 36.

The square root of 261161559 is about 16160.4937733969. The cubic root of 261161559 is about 639.1994866010.

The spelling of 261161559 in words is "two hundred sixty-one million, one hundred sixty-one thousand, five hundred fifty-nine".