261343181 has 16 divisors (see below), whose sum is σ = 299991168. Its totient is φ = 227228320.

The previous prime is 261343133. The next prime is 261343211. The reversal of 261343181 is 181343162.

It is not a de Polignac number, because 261343181 - 2¹⁰ = 261342157 is a prime.

It is a super-2 number, since 2×261343181² = 136600516510397522, which contains 22 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 (261348181) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26345 + ... + 34881.

It is an arithmetic number, because the mean of its divisors is an integer number (18749448).

Almost surely, 2^261343181 is an apocalyptic number.

It is an amenable number.

261343181 is a deficient number, since it is larger than the sum of its proper divisors (38647987).

261343181 is an equidigital number, since it uses as much as digits as its factorization.

261343181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8593 (or 8571 counting only the distinct ones).

The product of its digits is 3456, while the sum is 29.

The square root of 261343181 is about 16166.1121176367. The cubic root of 261343181 is about 639.3476270703.

The spelling of 261343181 in words is "two hundred sixty-one million, three hundred forty-three thousand, one hundred eighty-one".