261839887 has 4 divisors (see below), whose sum is σ = 262193040. Its totient is φ = 261486736.

The previous prime is 261839873. The next prime is 261839923. The reversal of 261839887 is 788938162.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-261839887 is a prime.

It is a super-3 number, since 3×261839887³ (a number of 26 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261839087) 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 3 ways as a sum of consecutive naturals, for example, 175462 + ... + 176947.

It is an arithmetic number, because the mean of its divisors is an integer number (65548260).

Almost surely, 2^261839887 is an apocalyptic number.

261839887 is a deficient number, since it is larger than the sum of its proper divisors (353153).

261839887 is an equidigital number, since it uses as much as digits as its factorization.

261839887 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 353152.

The product of its digits is 1161216, while the sum is 52.

The square root of 261839887 is about 16181.4673932867. The cubic root of 261839887 is about 639.7524164419.

The spelling of 261839887 in words is "two hundred sixty-one million, eight hundred thirty-nine thousand, eight hundred eighty-seven".