261616161 has 8 divisors (see below), whose sum is σ = 360073984. Its totient is φ = 168784560.

The previous prime is 261616151. The next prime is 261616169. The reversal of 261616161 is 161616162.

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

It is not a de Polignac number, because 261616161 - 2⁶ = 261616097 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (261616169) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1406446 + ... + 1406631.

It is an arithmetic number, because the mean of its divisors is an integer number (45009248).

Almost surely, 2^261616161 is an apocalyptic number.

It is an amenable number.

261616161 is a deficient number, since it is larger than the sum of its proper divisors (98457823).

261616161 is a wasteful number, since it uses less digits than its factorization.

261616161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2813111.

The product of its digits is 2592, while the sum is 30.

The square root of 261616161 is about 16174.5528840831. The cubic root of 261616161 is about 639.5701548886.

Subtracting from 261616161 its reverse (161616162), we obtain a palindrome (99999999).

The spelling of 261616161 in words is "two hundred sixty-one million, six hundred sixteen thousand, one hundred sixty-one".