2156807729 has 2 divisors, whose sum is σ = 2156807730. Its totient is φ = 2156807728.

The previous prime is 2156807713. The next prime is 2156807759. The reversal of 2156807729 is 9277086512.

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., 1486256704 + 670551025 = 38552^2 + 25895^2 .

It is a cyclic number.

It is not a de Polignac number, because 2156807729 - 2⁴ = 2156807713 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (2156807759) 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, 1078403864 + 1078403865.

It is an arithmetic number, because the mean of its divisors is an integer number (1078403865).

Almost surely, 2^2156807729 is an apocalyptic number.

It is an amenable number.

2156807729 is a deficient number, since it is larger than the sum of its proper divisors (1).

2156807729 is an equidigital number, since it uses as much as digits as its factorization.

2156807729 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 423360, while the sum is 47.

The square root of 2156807729 is about 46441.4440882279. Note that the first 3 decimals coincide. The cubic root of 2156807729 is about 1292.0236908451.

The spelling of 2156807729 in words is "two billion, one hundred fifty-six million, eight hundred seven thousand, seven hundred twenty-nine".