1161981568 has 64 divisors (see below), whose sum is σ = 2550644640. Its totient is φ = 522880000.

The previous prime is 1161981563. The next prime is 1161981581. The reversal of 1161981568 is 8651891611.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (64).

It is not an unprimeable number, because it can be changed into a prime (1161981563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 138123 + ... + 146293.

Almost surely, 2^1161981568 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1161981568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1275322320).

1161981568 is an abundant number, since it is smaller than the sum of its proper divisors (1388663072).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1161981568 is a wasteful number, since it uses less digits than its factorization.

1161981568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8297 (or 8285 counting only the distinct ones).

The product of its digits is 103680, while the sum is 46.

The square root of 1161981568 is about 34087.8507389363. The cubic root of 1161981568 is about 1051.3155296375.

The spelling of 1161981568 in words is "one billion, one hundred sixty-one million, nine hundred eighty-one thousand, five hundred sixty-eight".