7978999 has 8 divisors (see below), whose sum is σ = 9515520. Its totient is φ = 6541656.

The previous prime is 7978981. The next prime is 7979009. The reversal of 7978999 is 9998797.

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

It is a cyclic number.

It is not a de Polignac number, because 7978999 - 2⁷ = 7978871 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7978979) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24619 + ... + 24940.

It is an arithmetic number, because the mean of its divisors is an integer number (1189440).

Almost surely, 2^7978999 is an apocalyptic number.

7978999 is a deficient number, since it is larger than the sum of its proper divisors (1536521).

7978999 is a wasteful number, since it uses less digits than its factorization.

7978999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49589.

The product of its digits is 2571912, while the sum is 58.

The square root of 7978999 is about 2824.7121977292. The cubic root of 7978999 is about 199.8248383034.

The spelling of 7978999 in words is "seven million, nine hundred seventy-eight thousand, nine hundred ninety-nine".