19980139187 has 4 divisors (see below), whose sum is σ = 21031725480. Its totient is φ = 18928552896.

The previous prime is 19980139171. The next prime is 19980139213. The reversal of 19980139187 is 78193108991.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 19980139187 - 2⁴ = 19980139171 is a prime.

It is not an unprimeable number, because it can be changed into a prime (19980139787) 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 3 ways as a sum of consecutive naturals, for example, 525793118 + ... + 525793155.

It is an arithmetic number, because the mean of its divisors is an integer number (5257931370).

Almost surely, 2^19980139187 is an apocalyptic number.

19980139187 is a deficient number, since it is larger than the sum of its proper divisors (1051586293).

19980139187 is a wasteful number, since it uses less digits than its factorization.

19980139187 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1051586292.

The product of its (nonzero) digits is 979776, while the sum is 56.

The spelling of 19980139187 in words is "nineteen billion, nine hundred eighty million, one hundred thirty-nine thousand, one hundred eighty-seven".