19920517939 has 4 divisors (see below), whose sum is σ = 22766306224. Its totient is φ = 17074729656.

The previous prime is 19920517927. The next prime is 19920517957. The reversal of 19920517939 is 93971502991.

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 19920517939 - 2¹⁷ = 19920386867 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 19920517939.

It is not an unprimeable number, because it can be changed into a prime (19920517039) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1422894132 + ... + 1422894145.

It is an arithmetic number, because the mean of its divisors is an integer number (5691576556).

Almost surely, 2^19920517939 is an apocalyptic number.

19920517939 is a deficient number, since it is larger than the sum of its proper divisors (2845788285).

19920517939 is an equidigital number, since it uses as much as digits as its factorization.

19920517939 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2845788284.

The product of its (nonzero) digits is 1377810, while the sum is 55.

The spelling of 19920517939 in words is "nineteen billion, nine hundred twenty million, five hundred seventeen thousand, nine hundred thirty-nine".