2165154661 has 2 divisors, whose sum is σ = 2165154662. Its totient is φ = 2165154660.

The previous prime is 2165154637. The next prime is 2165154689. The reversal of 2165154661 is 1664515612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1745150625 + 420004036 = 41775^2 + 20494^2 .

It is a cyclic number.

It is not a de Polignac number, because 2165154661 - 2⁹ = 2165154149 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 2165154661.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2165154461) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1082577330 + 1082577331.

It is an arithmetic number, because the mean of its divisors is an integer number (1082577331).

Almost surely, 2^2165154661 is an apocalyptic number.

It is an amenable number.

2165154661 is a deficient number, since it is larger than the sum of its proper divisors (1).

2165154661 is an equidigital number, since it uses as much as digits as its factorization.

2165154661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 43200, while the sum is 37.

The square root of 2165154661 is about 46531.2224318253. Note that the first 3 decimals coincide. The cubic root of 2165154661 is about 1293.6882731065.

The spelling of 2165154661 in words is "two billion, one hundred sixty-five million, one hundred fifty-four thousand, six hundred sixty-one".