78428640 has 48 divisors (see below), whose sum is σ = 247051728. Its totient is φ = 20914176.

The previous prime is 78428627. The next prime is 78428677. The reversal of 78428640 is 4682487.

It is a tau number, because it is divible by the number of its divisors (48).

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 81217 + ... + 82176.

It is an arithmetic number, because the mean of its divisors is an integer number (5146911).

Almost surely, 2^78428640 is an apocalyptic number.

It is an amenable number.

78428640 is an abundant number, since it is smaller than the sum of its proper divisors (168623088).

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

78428640 is a wasteful number, since it uses less digits than its factorization.

78428640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 163411 (or 163403 counting only the distinct ones).

The product of its (nonzero) digits is 86016, while the sum is 39.

The square root of 78428640 is about 8855.9945799441. The cubic root of 78428640 is about 428.0471022782.

The spelling of 78428640 in words is "seventy-eight million, four hundred twenty-eight thousand, six hundred forty".