2661228729 has 16 divisors (see below), whose sum is σ = 3943852800. Its totient is φ = 1773571248.

The previous prime is 2661228727. The next prime is 2661228743. The reversal of 2661228729 is 9278221662.

2661228729 is a `hidden beast` number, since 2 + 6 + 612 + 2 + 8 + 7 + 29 = 666.

It is not a de Polignac number, because 2661228729 - 2¹ = 2661228727 is a prime.

It is not an unprimeable number, because it can be changed into a prime (2661228727) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 77712 + ... + 106590.

It is an arithmetic number, because the mean of its divisors is an integer number (246490800).

Almost surely, 2^2661228729 is an apocalyptic number.

It is an amenable number.

2661228729 is a deficient number, since it is larger than the sum of its proper divisors (1282624071).

2661228729 is a wasteful number, since it uses less digits than its factorization.

2661228729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32301 (or 32295 counting only the distinct ones).

The product of its digits is 290304, while the sum is 45.

The square root of 2661228729 is about 51587.0984743279. The cubic root of 2661228729 is about 1385.7792933924.

The spelling of 2661228729 in words is "two billion, six hundred sixty-one million, two hundred twenty-eight thousand, seven hundred twenty-nine".