261338181 has 16 divisors (see below), whose sum is σ = 375871104. Its totient is φ = 160559424.

The previous prime is 261338173. The next prime is 261338183. The reversal of 261338181 is 181833162.

It is not a de Polignac number, because 261338181 - 2³ = 261338173 is a prime.

It is a super-2 number, since 2×261338181² = 136595289696777522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261338183) 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, 20055 + ... + 30411.

It is an arithmetic number, because the mean of its divisors is an integer number (23491944).

Almost surely, 2^261338181 is an apocalyptic number.

It is an amenable number.

261338181 is a deficient number, since it is larger than the sum of its proper divisors (114532923).

261338181 is a wasteful number, since it uses less digits than its factorization.

261338181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11020.

The product of its digits is 6912, while the sum is 33.

The square root of 261338181 is about 16165.9574724172. The cubic root of 261338181 is about 639.3435497258.

The spelling of 261338181 in words is "two hundred sixty-one million, three hundred thirty-eight thousand, one hundred eighty-one".