78400028 has 12 divisors (see below), whose sum is σ = 156800112. Its totient is φ = 33600000.

The previous prime is 78400027. The next prime is 78400033. The reversal of 78400028 is 82000487.

78400028 is an admirable number.

It is a super-2 number, since 2×78400028² = 12293128780801568, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (78400027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1399973 + ... + 1400028.

It is an arithmetic number, because the mean of its divisors is an integer number (13066676).

Almost surely, 2^78400028 is an apocalyptic number.

It is an amenable number.

78400028 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

78400028 is a wasteful number, since it uses less digits than its factorization.

78400028 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2800012 (or 2800010 counting only the distinct ones).

The product of its (nonzero) digits is 3584, while the sum is 29.

The square root of 78400028 is about 8854.3790296102. The cubic root of 78400028 is about 427.9950431778.

It can be divided in two parts, 784000 and 28, that multiplied together give a cube (21952000 = 280³).

The spelling of 78400028 in words is "seventy-eight million, four hundred thousand, twenty-eight".