138641979 has 8 divisors (see below), whose sum is σ = 211264000. Its totient is φ = 79223976.

The previous prime is 138641977. The next prime is 138641989. The reversal of 138641979 is 979146831.

It is a happy number.

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

It is not a de Polignac number, because 138641979 - 2¹ = 138641977 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (138641977) 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, 3300979 + ... + 3301020.

It is an arithmetic number, because the mean of its divisors is an integer number (26408000).

Almost surely, 2^138641979 is an apocalyptic number.

138641979 is a deficient number, since it is larger than the sum of its proper divisors (72622021).

138641979 is an equidigital number, since it uses as much as digits as its factorization.

138641979 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6602009.

The product of its digits is 326592, while the sum is 48.

The square root of 138641979 is about 11774.6328605184. The cubic root of 138641979 is about 517.5650197191.

It can be divided in two parts, 1386 and 41979, that added together give a triangular number (43365 = T₂₉₄).

The spelling of 138641979 in words is "one hundred thirty-eight million, six hundred forty-one thousand, nine hundred seventy-nine".