78389856 has 144 divisors (see below), whose sum is σ = 245188944. Its totient is φ = 24551424.

The previous prime is 78389851. The next prime is 78389867. The reversal of 78389856 is 65898387.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (144).

It is a super-2 number, since 2×78389856² = 12289939047401472, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an alternating number because its digits alternate between odd and even.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78389851) 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, 131896 + ... + 132488.

It is an arithmetic number, because the mean of its divisors is an integer number (1702701).

Almost surely, 2^78389856 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 78389856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (122594472).

78389856 is an abundant number, since it is smaller than the sum of its proper divisors (166799088).

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

78389856 is a wasteful number, since it uses less digits than its factorization.

78389856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 635 (or 615 counting only the distinct ones).

The product of its digits is 2903040, while the sum is 54.

The square root of 78389856 is about 8853.8046059307. The cubic root of 78389856 is about 427.9765323261.

The spelling of 78389856 in words is "seventy-eight million, three hundred eighty-nine thousand, eight hundred fifty-six".