261660111 has 4 divisors (see below), whose sum is σ = 348880152. Its totient is φ = 174440072.

The previous prime is 261660101. The next prime is 261660137. The reversal of 261660111 is 111066162.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 261660111 - 2⁵ = 261660079 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (261660101) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 43610016 + ... + 43610021.

It is an arithmetic number, because the mean of its divisors is an integer number (87220038).

Almost surely, 2^261660111 is an apocalyptic number.

261660111 is a deficient number, since it is larger than the sum of its proper divisors (87220041).

261660111 is an equidigital number, since it uses as much as digits as its factorization.

261660111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87220040.

The product of its (nonzero) digits is 432, while the sum is 24.

The square root of 261660111 is about 16175.9114426359. The cubic root of 261660111 is about 639.6059675773.

The spelling of 261660111 in words is "two hundred sixty-one million, six hundred sixty thousand, one hundred eleven".