261916571 has 16 divisors (see below), whose sum is σ = 319002624. Its totient is φ = 210164064.

The previous prime is 261916561. The next prime is 261916573. The reversal of 261916571 is 175619162.

It is not a de Polignac number, because 261916571 - 2¹⁴ = 261900187 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261916573) 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 15 ways as a sum of consecutive naturals, for example, 9740 + ... + 24873.

It is an arithmetic number, because the mean of its divisors is an integer number (19937664).

Almost surely, 2^261916571 is an apocalyptic number.

261916571 is a deficient number, since it is larger than the sum of its proper divisors (57086053).

261916571 is a wasteful number, since it uses less digits than its factorization.

261916571 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 34690.

The product of its digits is 22680, while the sum is 38.

The square root of 261916571 is about 16183.8367206296. The cubic root of 261916571 is about 639.8148642561.

The spelling of 261916571 in words is "two hundred sixty-one million, nine hundred sixteen thousand, five hundred seventy-one".