78776640 has 168 divisors, whose sum is σ = 287075880. Its totient is φ = 19759104.

The previous prime is 78776597. The next prime is 78776651. The reversal of 78776640 is 4667787.

It can be written as a sum of positive squares in 4 ways, for example, as 39538944 + 39237696 = 6288^2 + 6264^2 .

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 48156 + ... + 49764.

It is an arithmetic number, because the mean of its divisors is an integer number (1708785).

Almost surely, 2^78776640 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 78776640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (143537940).

78776640 is an abundant number, since it is smaller than the sum of its proper divisors (208299240).

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

78776640 is a wasteful number, since it uses less digits than its factorization.

78776640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1649 (or 1636 counting only the distinct ones).

The product of its (nonzero) digits is 395136, while the sum is 45.

The square root of 78776640 is about 8875.6205416861. The cubic root of 78776640 is about 428.6792719082.

The spelling of 78776640 in words is "seventy-eight million, seven hundred seventy-six thousand, six hundred forty".