261161560 has 48 divisors (see below), whose sum is σ = 645901200. Its totient is φ = 94966080.

The previous prime is 261161543. The next prime is 261161567. The reversal of 261161560 is 65161162.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261161567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 22140 + ... + 31819.

It is an arithmetic number, because the mean of its divisors is an integer number (13456275).

Almost surely, 2^261161560 is an apocalyptic number.

261161560 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

261161560 is an abundant number, since it is smaller than the sum of its proper divisors (384739640).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

261161560 is a wasteful number, since it uses less digits than its factorization.

261161560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 53992 (or 53977 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 261161560 is about 16160.4938043365. The cubic root of 261161560 is about 639.1994874168.

The spelling of 261161560 in words is "two hundred sixty-one million, one hundred sixty-one thousand, five hundred sixty".