78243818 has 4 divisors (see below), whose sum is σ = 117365730. Its totient is φ = 39121908.

The previous prime is 78243757. The next prime is 78243839. The reversal of 78243818 is 81834287.

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

It can be written as a sum of positive squares in only one way, i.e., 68277169 + 9966649 = 8263^2 + 3157^2 .

It is a super-2 number, since 2×78243818² = 12244190110434248, which contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 19560953 + ... + 19560956.

Almost surely, 2^78243818 is an apocalyptic number.

78243818 is a deficient number, since it is larger than the sum of its proper divisors (39121912).

78243818 is a wasteful number, since it uses less digits than its factorization.

78243818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39121911.

The product of its digits is 86016, while the sum is 41.

The square root of 78243818 is about 8845.5535722757. The cubic root of 78243818 is about 427.7105978772.

The spelling of 78243818 in words is "seventy-eight million, two hundred forty-three thousand, eight hundred eighteen".