870128729 has 4 divisors (see below), whose sum is σ = 870213540. Its totient is φ = 870043920.

The previous prime is 870128723. The next prime is 870128761. The reversal of 870128729 is 927821078.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 457104400 + 413024329 = 21380^2 + 20323^2 .

It is a cyclic number.

It is not a de Polignac number, because 870128729 - 2⁴ = 870128713 is a prime.

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 870128729.

It is not an unprimeable number, because it can be changed into a prime (870128723) 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 3 ways as a sum of consecutive naturals, for example, 24494 + ... + 48375.

It is an arithmetic number, because the mean of its divisors is an integer number (217553385).

Almost surely, 2^870128729 is an apocalyptic number.

It is an amenable number.

870128729 is a deficient number, since it is larger than the sum of its proper divisors (84811).

870128729 is a wasteful number, since it uses less digits than its factorization.

870128729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84810.

The product of its (nonzero) digits is 112896, while the sum is 44.

The square root of 870128729 is about 29497.9444877096. The cubic root of 870128729 is about 954.6873528620.

The spelling of 870128729 in words is "eight hundred seventy million, one hundred twenty-eight thousand, seven hundred twenty-nine".