78857489 has 4 divisors (see below), whose sum is σ = 79359924. Its totient is φ = 78355056.

The previous prime is 78857461. The next prime is 78857507. The reversal of 78857489 is 98475887.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 98475887 = 239 ⋅412033.

It can be written as a sum of positive squares in 2 ways, for example, as 43335889 + 35521600 = 6583^2 + 5960^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-78857489 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78857419) 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 in 3 ways as a sum of consecutive naturals, for example, 250982 + ... + 251295.

It is an arithmetic number, because the mean of its divisors is an integer number (19839981).

Almost surely, 2^78857489 is an apocalyptic number.

It is an amenable number.

78857489 is a deficient number, since it is larger than the sum of its proper divisors (502435).

78857489 is a wasteful number, since it uses less digits than its factorization.

78857489 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 502434.

The product of its digits is 4515840, while the sum is 56.

The square root of 78857489 is about 8880.1739284769. The cubic root of 78857489 is about 428.8258739150.

The spelling of 78857489 in words is "seventy-eight million, eight hundred fifty-seven thousand, four hundred eighty-nine".