2165721133 has 2 divisors, whose sum is σ = 2165721134. Its totient is φ = 2165721132.

The previous prime is 2165721127. The next prime is 2165721167. The reversal of 2165721133 is 3311275612.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1716196329 + 449524804 = 41427^2 + 21202^2 .

It is a cyclic number.

It is not a de Polignac number, because 2165721133 - 2⁹ = 2165720621 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 2165721095 and 2165721104.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2165721533) 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 as a sum of consecutive naturals, namely, 1082860566 + 1082860567.

It is an arithmetic number, because the mean of its divisors is an integer number (1082860567).

Almost surely, 2^2165721133 is an apocalyptic number.

It is an amenable number.

2165721133 is a deficient number, since it is larger than the sum of its proper divisors (1).

2165721133 is an equidigital number, since it uses as much as digits as its factorization.

2165721133 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7560, while the sum is 31.

The square root of 2165721133 is about 46537.3090433901. The cubic root of 2165721133 is about 1293.8010863380.

Adding to 2165721133 its reverse (3311275612), we get a palindrome (5476996745).

The spelling of 2165721133 in words is "two billion, one hundred sixty-five million, seven hundred twenty-one thousand, one hundred thirty-three".