1165001661 has 12 divisors (see below), whose sum is σ = 1687024092. Its totient is φ = 774709056.

The previous prime is 1165001603. The next prime is 1165001699. The reversal of 1165001661 is 1661005611.

1165001661 is a `hidden beast` number, since 1 + 1 + 650 + 0 + 1 + 6 + 6 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 1054625625 + 110376036 = 32475^2 + 10506^2 .

It is not a de Polignac number, because 1165001661 - 2⁶ = 1165001597 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1165008661) 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, 159456 + ... + 166601.

It is an arithmetic number, because the mean of its divisors is an integer number (140585341).

Almost surely, 2^1165001661 is an apocalyptic number.

It is an amenable number.

1165001661 is a deficient number, since it is larger than the sum of its proper divisors (522022431).

1165001661 is a wasteful number, since it uses less digits than its factorization.

1165001661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 326460 (or 326457 counting only the distinct ones).

The product of its (nonzero) digits is 1080, while the sum is 27.

The square root of 1165001661 is about 34132.1206636798. The cubic root of 1165001661 is about 1052.2255623956.

The spelling of 1165001661 in words is "one billion, one hundred sixty-five million, one thousand, six hundred sixty-one".