19890874643 has 2 divisors, whose sum is σ = 19890874644. Its totient is φ = 19890874642.

The previous prime is 19890874637. The next prime is 19890874673. The reversal of 19890874643 is 34647809891.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 19890874643 - 2⁶ = 19890874579 is a prime.

It is not a weakly prime, because it can be changed into another prime (19890874673) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9945437321 + 9945437322.

It is an arithmetic number, because the mean of its divisors is an integer number (9945437322).

Almost surely, 2^19890874643 is an apocalyptic number.

19890874643 is a deficient number, since it is larger than the sum of its proper divisors (1).

19890874643 is an equidigital number, since it uses as much as digits as its factorization.

19890874643 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10450944, while the sum is 59.

The spelling of 19890874643 in words is "nineteen billion, eight hundred ninety million, eight hundred seventy-four thousand, six hundred forty-three".