78647400 has 144 divisors (see below), whose sum is σ = 284526060. Its totient is φ = 19353600.

The previous prime is 78647369. The next prime is 78647407. The reversal of 78647400 is 474687.

It is a happy number.

78647400 is a `hidden beast` number, since 7 + 8 + 647 + 4 + 0 + 0 = 666.

It can be written as a sum of positive squares in 6 ways, for example, as 23561316 + 55086084 = 4854^2 + 7422^2 .

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

It is not an unprimeable number, because it can be changed into a prime (78647407) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 21720 + ... + 25080.

Almost surely, 2^78647400 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 78647400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (142263030).

78647400 is an abundant number, since it is smaller than the sum of its proper divisors (205878660).

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

78647400 is a wasteful number, since it uses less digits than its factorization.

78647400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3396 (or 3384 counting only the distinct ones).

The product of its (nonzero) digits is 37632, while the sum is 36.

The square root of 78647400 is about 8868.3369354124. The cubic root of 78647400 is about 428.4447149198. Note that the first 3 decimals are identical.

The spelling of 78647400 in words is "seventy-eight million, six hundred forty-seven thousand, four hundred".