261044181 has 16 divisors (see below), whose sum is σ = 403547520. Its totient is φ = 166462560.

The previous prime is 261044159. The next prime is 261044207. The reversal of 261044181 is 181440162.

It is a happy number.

261044181 is a `hidden beast` number, since 2 + 610 + 4 + 41 + 8 + 1 = 666.

It is not a de Polignac number, because 261044181 - 2¹⁸ = 260782037 is a prime.

It is a super-2 number, since 2×261044181² = 136288128867921522, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261044141) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 209560 + ... + 210801.

It is an arithmetic number, because the mean of its divisors is an integer number (25221720).

Almost surely, 2^261044181 is an apocalyptic number.

It is an amenable number.

261044181 is a deficient number, since it is larger than the sum of its proper divisors (142503339).

261044181 is a wasteful number, since it uses less digits than its factorization.

261044181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 420393 (or 420387 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 27.

The square root of 261044181 is about 16156.8617311655. The cubic root of 261044181 is about 639.1037103814.

The spelling of 261044181 in words is "two hundred sixty-one million, forty-four thousand, one hundred eighty-one".