261404161 has 8 divisors (see below), whose sum is σ = 266832000. Its totient is φ = 256009680.

The previous prime is 261404137. The next prime is 261404197. The reversal of 261404161 is 161404162.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 261404161 - 2¹³ = 261395969 is a prime.

It is a super-2 number, since 2×261404161² = 136664270776227842, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (261434161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7815 + ... + 24163.

It is an arithmetic number, because the mean of its divisors is an integer number (33354000).

Almost surely, 2^261404161 is an apocalyptic number.

It is an amenable number.

261404161 is a deficient number, since it is larger than the sum of its proper divisors (5427839).

261404161 is a wasteful number, since it uses less digits than its factorization.

261404161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16679.

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 261404161 is about 16167.9980517070. The cubic root of 261404161 is about 639.3973501792.

Subtracting from 261404161 its reverse (161404162), we obtain a palindrome (99999999).

The spelling of 261404161 in words is "two hundred sixty-one million, four hundred four thousand, one hundred sixty-one".