1161610261 has 4 divisors (see below), whose sum is σ = 1327554592. Its totient is φ = 995665932.

The previous prime is 1161610253. The next prime is 1161610267. The reversal of 1161610261 is 1620161611.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1161610261 - 2³ = 1161610253 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1161610267) 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 3 ways as a sum of consecutive naturals, for example, 82972155 + ... + 82972168.

It is an arithmetic number, because the mean of its divisors is an integer number (331888648).

Almost surely, 2^1161610261 is an apocalyptic number.

It is an amenable number.

1161610261 is a deficient number, since it is larger than the sum of its proper divisors (165944331).

1161610261 is an equidigital number, since it uses as much as digits as its factorization.

1161610261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 165944330.

The product of its (nonzero) digits is 432, while the sum is 25.

The square root of 1161610261 is about 34082.4039791796. The cubic root of 1161610261 is about 1051.2035363515.

Adding to 1161610261 its reverse (1620161611), we get a palindrome (2781771872).

The spelling of 1161610261 in words is "one billion, one hundred sixty-one million, six hundred ten thousand, two hundred sixty-one".