78218778 has 64 divisors (see below), whose sum is σ = 177292800. Its totient is φ = 22800960.

The previous prime is 78218761. The next prime is 78218809. The reversal of 78218778 is 87781287.

78218778 is a nontrivial binomial coefficient, being equal to C(12508, 2).

It is a super-2 number, since 2×78218778² = 12236354463626568, which contains 22 as substring.

It is a Smith number, since the sum of its digits (48) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 206193 + ... + 206571.

It is an arithmetic number, because the mean of its divisors is an integer number (2770200).

Almost surely, 2^78218778 is an apocalyptic number.

78218778 is the 12507-th triangular number and also the 6254-th hexagonal number.

It is a practical number, because each smaller number is the sum of distinct divisors of 78218778, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (88646400).

78218778 is an abundant number, since it is smaller than the sum of its proper divisors (99074022).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

78218778 is a wasteful number, since it uses less digits than its factorization.

78218778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 507.

The product of its digits is 351232, while the sum is 48.

The square root of 78218778 is about 8844.1380586239. The cubic root of 78218778 is about 427.6649669408.

The spelling of 78218778 in words is "seventy-eight million, two hundred eighteen thousand, seven hundred seventy-eight".