857750809 has 2 divisors, whose sum is σ = 857750810. Its totient is φ = 857750808.

The previous prime is 857750783. The next prime is 857750813. The reversal of 857750809 is 908057758.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 732243600 + 125507209 = 27060^2 + 11203^2 .

It is a cyclic number.

It is not a de Polignac number, because 857750809 - 2¹³ = 857742617 is a prime.

It is not a weakly prime, because it can be changed into another prime (857750009) 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 as a sum of consecutive naturals, namely, 428875404 + 428875405.

It is an arithmetic number, because the mean of its divisors is an integer number (428875405).

Almost surely, 2^857750809 is an apocalyptic number.

It is an amenable number.

857750809 is a deficient number, since it is larger than the sum of its proper divisors (1).

857750809 is an equidigital number, since it uses as much as digits as its factorization.

857750809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 705600, while the sum is 49.

The square root of 857750809 is about 29287.3831026263. The cubic root of 857750809 is about 950.1387826794.

The spelling of 857750809 in words is "eight hundred fifty-seven million, seven hundred fifty thousand, eight hundred nine".