78818 has 4 divisors (see below), whose sum is σ = 118230. Its totient is φ = 39408.

The previous prime is 78809. The next prime is 78823. The reversal of 78818 is 81887.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 81887 = 13 ⋅6299.

It can be written as a sum of positive squares in only one way, i.e., 66049 + 12769 = 257^2 + 113^2 .

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19703 + ... + 19706.

2⁷⁸⁸¹⁸ is an apocalyptic number.

78818 is a deficient number, since it is larger than the sum of its proper divisors (39412).

78818 is a wasteful number, since it uses less digits than its factorization.

78818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39411.

The product of its digits is 3584, while the sum is 32.

The square root of 78818 is about 280.7454362942. The cubic root of 78818 is about 42.8754281762.

The spelling of 78818 in words is "seventy-eight thousand, eight hundred eighteen".