7978139 has 8 divisors (see below), whose sum is σ = 8669472. Its totient is φ = 7297920.

The previous prime is 7978099. The next prime is 7978169. The reversal of 7978139 is 9318797.

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 7978139 - 2⁸ = 7977883 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 7978139.

It is not an unprimeable number, because it can be changed into a prime (7978169) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1247 + ... + 4184.

It is an arithmetic number, because the mean of its divisors is an integer number (1083684).

Almost surely, 2^7978139 is an apocalyptic number.

7978139 is a deficient number, since it is larger than the sum of its proper divisors (691333).

7978139 is a wasteful number, since it uses less digits than its factorization.

7978139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5557.

The product of its digits is 95256, while the sum is 44.

The square root of 7978139 is about 2824.5599657292. The cubic root of 7978139 is about 199.8176588090.

The spelling of 7978139 in words is "seven million, nine hundred seventy-eight thousand, one hundred thirty-nine".