78857129 has 8 divisors (see below), whose sum is σ = 85012872. Its totient is φ = 72714240.

The previous prime is 78857123. The next prime is 78857137. The reversal of 78857129 is 92175887.

It can be written as a sum of positive squares in 4 ways, for example, as 16810000 + 62047129 = 4100^2 + 7877^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 78857129 - 2¹⁶ = 78791593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78857123) 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 7 ways as a sum of consecutive naturals, for example, 12359 + ... + 17619.

It is an arithmetic number, because the mean of its divisors is an integer number (10626609).

Almost surely, 2^78857129 is an apocalyptic number.

It is an amenable number.

78857129 is a deficient number, since it is larger than the sum of its proper divisors (6155743).

78857129 is a wasteful number, since it uses less digits than its factorization.

78857129 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6427.

The product of its digits is 282240, while the sum is 47.

The square root of 78857129 is about 8880.1536585805. The cubic root of 78857129 is about 428.8252213558.

The spelling of 78857129 in words is "seventy-eight million, eight hundred fifty-seven thousand, one hundred twenty-nine".