17978139 has 8 divisors (see below), whose sum is σ = 26634320. Its totient is φ = 11985408.

The previous prime is 17978137. The next prime is 17978159. The reversal of 17978139 is 93187971.

It is not a de Polignac number, because 17978139 - 2¹ = 17978137 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 17978094 and 17978103.

It is not an unprimeable number, because it can be changed into a prime (17978137) 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 7 ways as a sum of consecutive naturals, for example, 332902 + ... + 332955.

It is an arithmetic number, because the mean of its divisors is an integer number (3329290).

Almost surely, 2^17978139 is an apocalyptic number.

17978139 is a deficient number, since it is larger than the sum of its proper divisors (8656181).

17978139 is an equidigital number, since it uses as much as digits as its factorization.

17978139 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 665866 (or 665860 counting only the distinct ones).

The product of its digits is 95256, while the sum is 45.

The square root of 17978139 is about 4240.0635608443. The cubic root of 17978139 is about 261.9680000931.

It can be divided in two parts, 17978 and 139, that multiplied together give a palindrome (2498942).

The spelling of 17978139 in words is "seventeen million, nine hundred seventy-eight thousand, one hundred thirty-nine".