261283287 has 4 divisors (see below), whose sum is σ = 348377720. Its totient is φ = 174188856.

The previous prime is 261283261. The next prime is 261283291. The reversal of 261283287 is 782382162.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 261283287 - 2⁸ = 261283031 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261283247) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 43547212 + ... + 43547217.

It is an arithmetic number, because the mean of its divisors is an integer number (87094430).

Almost surely, 2^261283287 is an apocalyptic number.

261283287 is a deficient number, since it is larger than the sum of its proper divisors (87094433).

261283287 is an equidigital number, since it uses as much as digits as its factorization.

261283287 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 87094432.

The product of its digits is 64512, while the sum is 39.

The square root of 261283287 is about 16164.2595561937. The cubic root of 261283287 is about 639.2987819563.

The spelling of 261283287 in words is "two hundred sixty-one million, two hundred eighty-three thousand, two hundred eighty-seven".