78546857 has 4 divisors (see below), whose sum is σ = 80462676. Its totient is φ = 76631040.

The previous prime is 78546841. The next prime is 78546859. The reversal of 78546857 is 75864587.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 75864587 = 19 ⋅3992873.

It can be written as a sum of positive squares in 2 ways, for example, as 36348841 + 42198016 = 6029^2 + 6496^2 .

It is a cyclic number.

It is not a de Polignac number, because 78546857 - 2⁴ = 78546841 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78546859) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 957848 + ... + 957929.

It is an arithmetic number, because the mean of its divisors is an integer number (20115669).

Almost surely, 2^78546857 is an apocalyptic number.

It is an amenable number.

78546857 is a deficient number, since it is larger than the sum of its proper divisors (1915819).

78546857 is a wasteful number, since it uses less digits than its factorization.

78546857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1915818.

The product of its digits is 1881600, while the sum is 50.

The square root of 78546857 is about 8862.6664723434. Note that the first 3 decimals coincide. The cubic root of 78546857 is about 428.2620621911.

The spelling of 78546857 in words is "seventy-eight million, five hundred forty-six thousand, eight hundred fifty-seven".