19988391906 has 24 divisors (see below), whose sum is σ = 49495065984. Its totient is φ = 5710969080.

The previous prime is 19988391893. The next prime is 19988391919. The reversal of 19988391906 is 60919388991.

It is an interprime number because it is at equal distance from previous prime (19988391893) and next prime (19988391919).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 79318890 + ... + 79319141.

It is an arithmetic number, because the mean of its divisors is an integer number (2062294416).

Almost surely, 2^19988391906 is an apocalyptic number.

19988391906 is an abundant number, since it is smaller than the sum of its proper divisors (29506674078).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

19988391906 is a wasteful number, since it uses less digits than its factorization.

19988391906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 158638046 (or 158638043 counting only the distinct ones).

The product of its (nonzero) digits is 7558272, while the sum is 63.

The spelling of 19988391906 in words is "nineteen billion, nine hundred eighty-eight million, three hundred ninety-one thousand, nine hundred six".