7978400 has 36 divisors (see below), whose sum is σ = 19479222. Its totient is φ = 3191040.

The previous prime is 7978381. The next prime is 7978403. The reversal of 7978400 is 48797.

It can be written as a sum of positive squares in 3 ways, for example, as 4276624 + 3701776 = 2068^2 + 1924^2 .

It is a hoax number, since the sum of its digits (35) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (7978403) by changing a digit.

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 5 ways as a sum of consecutive naturals, for example, 4187 + ... + 5786.

Almost surely, 2^7978400 is an apocalyptic number.

It is an amenable number.

7978400 is an abundant number, since it is smaller than the sum of its proper divisors (11500822).

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

7978400 is a wasteful number, since it uses less digits than its factorization.

7978400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9993 (or 9980 counting only the distinct ones).

The product of its (nonzero) digits is 14112, while the sum is 35.

The square root of 7978400 is about 2824.6061672382. The cubic root of 7978400 is about 199.8198377566.

The spelling of 7978400 in words is "seven million, nine hundred seventy-eight thousand, four hundred".