1161387661 has 12 divisors (see below), whose sum is σ = 1351806300. Its totient is φ = 994882560.

The previous prime is 1161387653. The next prime is 1161387713. The reversal of 1161387661 is 1667831611.

It can be written as a sum of positive squares in 2 ways, for example, as 608855625 + 552532036 = 24675^2 + 23506^2 .

It is not a de Polignac number, because 1161387661 - 2³ = 1161387653 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1161387631) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 89421 + ... + 101581.

It is an arithmetic number, because the mean of its divisors is an integer number (112650525).

Almost surely, 2^1161387661 is an apocalyptic number.

It is an amenable number.

1161387661 is a deficient number, since it is larger than the sum of its proper divisors (190418639).

1161387661 is a wasteful number, since it uses less digits than its factorization.

1161387661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14124 (or 14117 counting only the distinct ones).

The product of its digits is 36288, while the sum is 40.

The square root of 1161387661 is about 34079.1382080005. The cubic root of 1161387661 is about 1051.1363844952.

The spelling of 1161387661 in words is "one billion, one hundred sixty-one million, three hundred eighty-seven thousand, six hundred sixty-one".