261641611 has 32 divisors (see below), whose sum is σ = 348986880. Its totient is φ = 189888000.

The previous prime is 261641593. The next prime is 261641651. The reversal of 261641611 is 116146162.

It is a cyclic number.

It is not a de Polignac number, because 261641611 - 2⁷ = 261641483 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 261641611.

It is not an unprimeable number, because it can be changed into a prime (261641651) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 131220 + ... + 133198.

It is an arithmetic number, because the mean of its divisors is an integer number (10905840).

Almost surely, 2^261641611 is an apocalyptic number.

261641611 is a deficient number, since it is larger than the sum of its proper divisors (87345269).

261641611 is a wasteful number, since it uses less digits than its factorization.

261641611 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2115.

The product of its digits is 1728, while the sum is 28.

The square root of 261641611 is about 16175.3395945804. The cubic root of 261641611 is about 639.5908933280.

Adding to 261641611 its reverse (116146162), we get a palindrome (377787773).

The spelling of 261641611 in words is "two hundred sixty-one million, six hundred forty-one thousand, six hundred eleven".