77812218 has 64 divisors (see below), whose sum is σ = 190650240. Its totient is φ = 23328000.

The previous prime is 77812211. The next prime is 77812223. The reversal of 77812218 is 81221877.

It is a happy number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (77812211) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 59346 + ... + 60642.

It is an arithmetic number, because the mean of its divisors is an integer number (2978910).

Almost surely, 2^77812218 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 77812218, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (95325120).

77812218 is an abundant number, since it is smaller than the sum of its proper divisors (112838022).

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

77812218 is a wasteful number, since it uses less digits than its factorization.

77812218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1420 (or 1414 counting only the distinct ones).

The product of its digits is 12544, while the sum is 36.

The square root of 77812218 is about 8821.1233978445. The cubic root of 77812218 is about 426.9227172667.

It can be divided in two parts, 7781 and 2218, that added together give a palindrome (9999).

The spelling of 77812218 in words is "seventy-seven million, eight hundred twelve thousand, two hundred eighteen".