78440778 has 64 divisors (see below), whose sum is σ = 197635200. Its totient is φ = 22861440.

The previous prime is 78440767. The next prime is 78440801. The reversal of 78440778 is 87704487.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 10398 + ... + 16278.

It is an arithmetic number, because the mean of its divisors is an integer number (3088050).

Almost surely, 2^78440778 is an apocalyptic number.

78440778 is a gapful number since it is divisible by the number (78) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 78440778, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (98817600).

78440778 is an abundant number, since it is smaller than the sum of its proper divisors (119194422).

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

78440778 is a wasteful number, since it uses less digits than its factorization.

78440778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5924 (or 5918 counting only the distinct ones).

The product of its (nonzero) digits is 351232, while the sum is 45.

The square root of 78440778 is about 8856.6798519536. The cubic root of 78440778 is about 428.0691833603.

The spelling of 78440778 in words is "seventy-eight million, four hundred forty thousand, seven hundred seventy-eight".