2189721565 has 8 divisors (see below), whose sum is σ = 2628780120. Its totient is φ = 1751034432.

The previous prime is 2189721559. The next prime is 2189721581. The reversal of 2189721565 is 5651279812.

It can be written as a sum of positive squares in 4 ways, for example, as 33605209 + 2156116356 = 5797^2 + 46434^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 2189721565 - 2²⁷ = 2055503837 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 79714 + ... + 103603.

It is an arithmetic number, because the mean of its divisors is an integer number (328597515).

Almost surely, 2^2189721565 is an apocalyptic number.

It is an amenable number.

2189721565 is a deficient number, since it is larger than the sum of its proper divisors (439058555).

2189721565 is a wasteful number, since it uses less digits than its factorization.

2189721565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 185711.

The product of its digits is 302400, while the sum is 46.

The square root of 2189721565 is about 46794.4608367272. The cubic root of 2189721565 is about 1298.5628229991.

The spelling of 2189721565 in words is "two billion, one hundred eighty-nine million, seven hundred twenty-one thousand, five hundred sixty-five".