77978320 has 80 divisors (see below), whose sum is σ = 219414528. Its totient is φ = 25159680.

The previous prime is 77978281. The next prime is 77978323. The reversal of 77978320 is 2387977.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (77978323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5425 + ... + 13615.

Almost surely, 2^77978320 is an apocalyptic number.

77978320 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 77978320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (109707264).

77978320 is an abundant number, since it is smaller than the sum of its proper divisors (141436208).

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

77978320 is a wasteful number, since it uses less digits than its factorization.

77978320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8228 (or 8222 counting only the distinct ones).

The product of its (nonzero) digits is 148176, while the sum is 43.

The square root of 77978320 is about 8830.5333927232. The cubic root of 77978320 is about 427.2262785015.

The spelling of 77978320 in words is "seventy-seven million, nine hundred seventy-eight thousand, three hundred twenty".