1171345261 has 4 divisors (see below), whose sum is σ = 1209130624. Its totient is φ = 1133559900.

The previous prime is 1171345249. The next prime is 1171345319. The reversal of 1171345261 is 1625431711.

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 1171345261 - 2²⁹ = 634474349 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31), and also a Moran number because the ratio is a prime number: 37785331 = 1171345261 / (1 + 1 + 7 + 1 + 3 + 4 + 5 + 2 + 6 + 1).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1171345211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 18892635 + ... + 18892696.

It is an arithmetic number, because the mean of its divisors is an integer number (302282656).

Almost surely, 2^1171345261 is an apocalyptic number.

It is an amenable number.

1171345261 is a deficient number, since it is larger than the sum of its proper divisors (37785363).

1171345261 is an equidigital number, since it uses as much as digits as its factorization.

1171345261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37785362.

The product of its digits is 5040, while the sum is 31.

The square root of 1171345261 is about 34224.9216361411. The cubic root of 1171345261 is about 1054.1319457542.

Adding to 1171345261 its reverse (1625431711), we get a palindrome (2796776972).

The spelling of 1171345261 in words is "one billion, one hundred seventy-one million, three hundred forty-five thousand, two hundred sixty-one".