78643800 has 72 divisors (see below), whose sum is σ = 264118140. Its totient is φ = 20971200.

The previous prime is 78643783. The next prime is 78643801. The reversal of 78643800 is 834687.

78643800 is a `hidden beast` number, since 7 + 8 + 643 + 8 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (72).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78643801) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 20046 + ... + 23645.

Almost surely, 2^78643800 is an apocalyptic number.

It is an amenable number.

78643800 is an abundant number, since it is smaller than the sum of its proper divisors (185474340).

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

78643800 is a wasteful number, since it uses less digits than its factorization.

78643800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43713 (or 43701 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 36.

The square root of 78643800 is about 8868.1339638055. The cubic root of 78643800 is about 428.4381776217.

It can be divided in two parts, 7864 and 3800, that added together give a square (11664 = 108²).

The spelling of 78643800 in words is "seventy-eight million, six hundred forty-three thousand, eight hundred".