78870857 has 4 divisors (see below), whose sum is σ = 84937860. Its totient is φ = 72803856.

The previous prime is 78870853. The next prime is 78870893. The reversal of 78870857 is 75807887.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 29365561 + 49505296 = 5419^2 + 7036^2 .

It is a cyclic number.

It is not a de Polignac number, because 78870857 - 2² = 78870853 is a prime.

It is a super-2 number, since 2×78870857² = 12441224167828898, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (78870853) 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, 3033482 + ... + 3033507.

It is an arithmetic number, because the mean of its divisors is an integer number (21234465).

Almost surely, 2^78870857 is an apocalyptic number.

It is an amenable number.

78870857 is a deficient number, since it is larger than the sum of its proper divisors (6067003).

78870857 is a wasteful number, since it uses less digits than its factorization.

78870857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6067002.

The product of its (nonzero) digits is 878080, while the sum is 50.

The square root of 78870857 is about 8880.9265845406. The cubic root of 78870857 is about 428.8501042088.

The spelling of 78870857 in words is "seventy-eight million, eight hundred seventy thousand, eight hundred fifty-seven".