2165228729 has 4 divisors (see below), whose sum is σ = 2177744676. Its totient is φ = 2152712784.

The previous prime is 2165228701. The next prime is 2165228731. The reversal of 2165228729 is 9278225612.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1888771600 + 276457129 = 43460^2 + 16627^2 .

It is a cyclic number.

It is not a de Polignac number, because 2165228729 - 2⁸ = 2165228473 is a prime.

It is a super-3 number, since 3×2165228729³ (a number of 29 digits) contains 333 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2165228729.

It is not an unprimeable number, because it can be changed into a prime (2165228629) 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 in 3 ways as a sum of consecutive naturals, for example, 6257714 + ... + 6258059.

It is an arithmetic number, because the mean of its divisors is an integer number (544436169).

Almost surely, 2^2165228729 is an apocalyptic number.

It is an amenable number.

2165228729 is a deficient number, since it is larger than the sum of its proper divisors (12515947).

2165228729 is a wasteful number, since it uses less digits than its factorization.

2165228729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12515946.

The product of its digits is 241920, while the sum is 44.

The square root of 2165228729 is about 46532.0183207219. The cubic root of 2165228729 is about 1293.7030249103.

The spelling of 2165228729 in words is "two billion, one hundred sixty-five million, two hundred twenty-eight thousand, seven hundred twenty-nine".