1161578881 has 4 divisors (see below), whose sum is σ = 1173079764. Its totient is φ = 1150078000.

The previous prime is 1161578849. The next prime is 1161578893. The reversal of 1161578881 is 1888751611.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1888751611 = 101 ⋅18700511.

It can be written as a sum of positive squares in 2 ways, for example, as 583657281 + 577921600 = 24159^2 + 24040^2 .

It is a cyclic number.

It is not a de Polignac number, because 1161578881 - 2⁵ = 1161578849 is a prime.

It is a super-2 number, since 2×1161578881² = 2698530993570424322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1161578801) 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, 5750290 + ... + 5750491.

It is an arithmetic number, because the mean of its divisors is an integer number (293269941).

Almost surely, 2^1161578881 is an apocalyptic number.

It is an amenable number.

1161578881 is a deficient number, since it is larger than the sum of its proper divisors (11500883).

1161578881 is a wasteful number, since it uses less digits than its factorization.

1161578881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11500882.

The product of its digits is 107520, while the sum is 46.

The square root of 1161578881 is about 34081.9436212197. The cubic root of 1161578881 is about 1051.1940704502.

The spelling of 1161578881 in words is "one billion, one hundred sixty-one million, five hundred seventy-eight thousand, eight hundred eighty-one".