77780640 has 144 divisors (see below), whose sum is σ = 285096672. Its totient is φ = 17773056.

The previous prime is 77780609. The next prime is 77780653. The reversal of 77780640 is 4608777.

It is a happy 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 23 ways as a sum of consecutive naturals, for example, 21867 + ... + 25173.

It is an arithmetic number, because the mean of its divisors is an integer number (1979838).

Almost surely, 2^77780640 is an apocalyptic number.

77780640 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 77780640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (142548336).

77780640 is an abundant number, since it is smaller than the sum of its proper divisors (207316032).

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

77780640 is a wasteful number, since it uses less digits than its factorization.

77780640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3339 (or 3324 counting only the distinct ones).

The product of its (nonzero) digits is 65856, while the sum is 39.

The square root of 77780640 is about 8819.3333081362. Note that the first 4 decimals coincide. The cubic root of 77780640 is about 426.8649577442.

The spelling of 77780640 in words is "seventy-seven million, seven hundred eighty thousand, six hundred forty".