1161065988 has 90 divisors (see below), whose sum is σ = 3073676606. Its totient is φ = 382180032.

The previous prime is 1161065977. The next prime is 1161066007. The reversal of 1161065988 is 8895601611.

It can be written as a sum of positive squares in only one way, i.e., 626901444 + 534164544 = 25038^2 + 23112^2 .

It is a super-2 number, since 2×1161065988² = 2696148456980832288, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 29 ways as a sum of consecutive naturals, for example, 3709320 + ... + 3709632.

Almost surely, 2^1161065988 is an apocalyptic number.

1161065988 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1161065988, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1536838303).

1161065988 is an abundant number, since it is smaller than the sum of its proper divisors (1912610618).

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

1161065988 is a wasteful number, since it uses less digits than its factorization.

1161065988 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 543 (or 425 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 45.

The square root of 1161065988 is about 34074.4183809497. The cubic root of 1161065988 is about 1051.0393300757.

The spelling of 1161065988 in words is "one billion, one hundred sixty-one million, sixty-five thousand, nine hundred eighty-eight".