261589917 has 4 divisors (see below), whose sum is σ = 348786560. Its totient is φ = 174393276.

The previous prime is 261589903. The next prime is 261589943. The reversal of 261589917 is 719985162.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 261589917 - 2¹⁰ = 261588893 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 (261589987) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 43598317 + ... + 43598322.

It is an arithmetic number, because the mean of its divisors is an integer number (87196640).

Almost surely, 2^261589917 is an apocalyptic number.

It is an amenable number.

261589917 is a deficient number, since it is larger than the sum of its proper divisors (87196643).

261589917 is an equidigital number, since it uses as much as digits as its factorization.

261589917 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87196642.

The product of its digits is 272160, while the sum is 48.

The square root of 261589917 is about 16173.7415893788. The cubic root of 261589917 is about 639.5487680340.

The spelling of 261589917 in words is "two hundred sixty-one million, five hundred eighty-nine thousand, nine hundred seventeen".