78396840 has 96 divisors (see below), whose sum is σ = 259178400. Its totient is φ = 20545920.

The previous prime is 78396827. The next prime is 78396847. The reversal of 78396840 is 4869387.

It is a happy number.

It is a super-2 number, since 2×78396840² = 12292129043971200, which contains 22 as substring.

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

It is not an unprimeable number, because it can be changed into a prime (78396847) 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 23 ways as a sum of consecutive naturals, for example, 19395 + ... + 23085.

It is an arithmetic number, because the mean of its divisors is an integer number (2699775).

Almost surely, 2^78396840 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 78396840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (129589200).

78396840 is an abundant number, since it is smaller than the sum of its proper divisors (180781560).

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

78396840 is a wasteful number, since it uses less digits than its factorization.

78396840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3767 (or 3760 counting only the distinct ones).

The product of its (nonzero) digits is 290304, while the sum is 45.

The square root of 78396840 is about 8854.1990038625. The cubic root of 78396840 is about 427.9892418759.

The spelling of 78396840 in words is "seventy-eight million, three hundred ninety-six thousand, eight hundred forty".