78542640 has 240 divisors, whose sum is σ = 295266816. Its totient is φ = 18547200.

The previous prime is 78542627. The next prime is 78542657. The reversal of 78542640 is 4624587.

78542640 is a `hidden beast` number, since 7 + 8 + 5 + 4 + 2 + 640 = 666.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 78542595 and 78542604.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 372135 + ... + 372345.

Almost surely, 2^78542640 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 78542640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (147633408).

78542640 is an abundant number, since it is smaller than the sum of its proper divisors (216724176).

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

78542640 is a wasteful number, since it uses less digits than its factorization.

78542640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 288 (or 279 counting only the distinct ones).

The product of its (nonzero) digits is 53760, while the sum is 36.

The square root of 78542640 is about 8862.4285610661. The cubic root of 78542640 is about 428.2543979191.

The spelling of 78542640 in words is "seventy-eight million, five hundred forty-two thousand, six hundred forty".