261561595 has 8 divisors (see below), whose sum is σ = 319019760. Its totient is φ = 205818720.

The previous prime is 261561571. The next prime is 261561611. The reversal of 261561595 is 595165162.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 261561595 - 2¹⁷ = 261430523 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 428485 + ... + 429094.

It is an arithmetic number, because the mean of its divisors is an integer number (39877470).

Almost surely, 2^261561595 is an apocalyptic number.

261561595 is a deficient number, since it is larger than the sum of its proper divisors (57458165).

261561595 is an equidigital number, since it uses as much as digits as its factorization.

261561595 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 857645.

The product of its digits is 81000, while the sum is 40.

The square root of 261561595 is about 16172.8660106983. The cubic root of 261561595 is about 639.5256861632.

The spelling of 261561595 in words is "two hundred sixty-one million, five hundred sixty-one thousand, five hundred ninety-five".