19679012138 has 4 divisors (see below), whose sum is σ = 29518518210. Its totient is φ = 9839506068.

The previous prime is 19679012137. The next prime is 19679012149. The reversal of 19679012138 is 83121097691.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 83121097691 = 6569 ⋅12653539.

It can be written as a sum of positive squares in only one way, i.e., 16659839329 + 3019172809 = 129073^2 + 54947^2 .

It is a junction number, because it is equal to n+sod(n) for n = 19679012092 and 19679012101.

It is not an unprimeable number, because it can be changed into a prime (19679012131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4919753033 + ... + 4919753036.

Almost surely, 2^19679012138 is an apocalyptic number.

19679012138 is a deficient number, since it is larger than the sum of its proper divisors (9839506072).

19679012138 is an equidigital number, since it uses as much as digits as its factorization.

19679012138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9839506071.

The product of its (nonzero) digits is 163296, while the sum is 47.

The spelling of 19679012138 in words is "nineteen billion, six hundred seventy-nine million, twelve thousand, one hundred thirty-eight".