7978399 has 8 divisors (see below), whose sum is σ = 9373392. Its totient is φ = 6695040.

The previous prime is 7978381. The next prime is 7978403. The reversal of 7978399 is 9938797.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 7978399 - 2⁵ = 7978367 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7978319) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27754 + ... + 28039.

It is an arithmetic number, because the mean of its divisors is an integer number (1171674).

Almost surely, 2^7978399 is an apocalyptic number.

7978399 is a deficient number, since it is larger than the sum of its proper divisors (1394993).

7978399 is a wasteful number, since it uses less digits than its factorization.

7978399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55817.

The product of its digits is 857304, while the sum is 52.

The square root of 7978399 is about 2824.6059902224. The cubic root of 7978399 is about 199.8198294082.

The spelling of 7978399 in words is "seven million, nine hundred seventy-eight thousand, three hundred ninety-nine".