1161255511 has 4 divisors (see below), whose sum is σ = 1250582872. Its totient is φ = 1071928152.

The previous prime is 1161255503. The next prime is 1161255539. The reversal of 1161255511 is 1155521611.

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 1161255511 - 2³ = 1161255503 is a prime.

It is a super-2 number, since 2×1161255511² = 2697028723655742242, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1161255511.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1161255551) 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, 44663661 + ... + 44663686.

It is an arithmetic number, because the mean of its divisors is an integer number (312645718).

Almost surely, 2^1161255511 is an apocalyptic number.

1161255511 is a deficient number, since it is larger than the sum of its proper divisors (89327361).

1161255511 is an equidigital number, since it uses as much as digits as its factorization.

1161255511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89327360.

The product of its digits is 1500, while the sum is 28.

The square root of 1161255511 is about 34077.1992833918. The cubic root of 1161255511 is about 1051.0965146777.

The spelling of 1161255511 in words is "one billion, one hundred sixty-one million, two hundred fifty-five thousand, five hundred eleven".