78315840 has 168 divisors, whose sum is σ = 273881088. Its totient is φ = 20536320.

The previous prime is 78315823. The next prime is 78315841. The reversal of 78315840 is 4851387.

78315840 is a `hidden beast` number, since 78 + 3 + 1 + 584 + 0 = 666.

It is a super-2 number, since 2×78315840² = 12266741589811200, which contains 22 as substring.

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 = 78315795 and 78315804.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78315841) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 204289 + ... + 204671.

Almost surely, 2^78315840 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 78315840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (136940544).

78315840 is an abundant number, since it is smaller than the sum of its proper divisors (195565248).

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

78315840 is a wasteful number, since it uses less digits than its factorization.

78315840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 477 (or 464 counting only the distinct ones).

The product of its (nonzero) digits is 26880, while the sum is 36.

The square root of 78315840 is about 8849.6237208143. The cubic root of 78315840 is about 427.8417908865.

The spelling of 78315840 in words is "seventy-eight million, three hundred fifteen thousand, eight hundred forty".