78641728 has 56 divisors (see below), whose sum is σ = 180283104. Its totient is φ = 33638400.

The previous prime is 78641723. The next prime is 78641729. The reversal of 78641728 is 82714687.

It is not an unprimeable number, because it can be changed into a prime (78641723) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8683 + ... + 15253.

Almost surely, 2^78641728 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 78641728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (90141552).

78641728 is an abundant number, since it is smaller than the sum of its proper divisors (101641376).

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

78641728 is a wasteful number, since it uses less digits than its factorization.

78641728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6611 (or 6601 counting only the distinct ones).

The product of its digits is 150528, while the sum is 43.

The square root of 78641728 is about 8868.0171402631. The cubic root of 78641728 is about 428.4344149530.

The spelling of 78641728 in words is "seventy-eight million, six hundred forty-one thousand, seven hundred twenty-eight".