19890391709 has 8 divisors (see below), whose sum is σ = 20657985792. Its totient is φ = 19130670720.

The previous prime is 19890391693. The next prime is 19890391723. The reversal of 19890391709 is 90719309891.

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

It is a cyclic number.

It is not a de Polignac number, because 19890391709 - 2⁴ = 19890391693 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19890391109) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1963124 + ... + 1973229.

It is an arithmetic number, because the mean of its divisors is an integer number (2582248224).

Almost surely, 2^19890391709 is an apocalyptic number.

It is an amenable number.

19890391709 is a deficient number, since it is larger than the sum of its proper divisors (767594083).

19890391709 is a wasteful number, since it uses less digits than its factorization.

19890391709 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3936547.

The product of its (nonzero) digits is 1102248, while the sum is 56.

The spelling of 19890391709 in words is "nineteen billion, eight hundred ninety million, three hundred ninety-one thousand, seven hundred nine".