261348665 has 4 divisors (see below), whose sum is σ = 313618404. Its totient is φ = 209078928.

The previous prime is 261348643. The next prime is 261348691. The reversal of 261348665 is 566843162.

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

It can be written as a sum of positive squares in 2 ways, for example, as 119333776 + 142014889 = 10924^2 + 11917^2 .

It is a cyclic number.

It is not a de Polignac number, because 261348665 - 2¹⁸ = 261086521 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26134862 + ... + 26134871.

It is an arithmetic number, because the mean of its divisors is an integer number (78404601).

Almost surely, 2^261348665 is an apocalyptic number.

It is an amenable number.

261348665 is a deficient number, since it is larger than the sum of its proper divisors (52269739).

261348665 is an equidigital number, since it uses as much as digits as its factorization.

261348665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 52269738.

The product of its digits is 207360, while the sum is 41.

The square root of 261348665 is about 16166.2817308124. The cubic root of 261348665 is about 639.3520990419.

The spelling of 261348665 in words is "two hundred sixty-one million, three hundred forty-eight thousand, six hundred sixty-five".