1989509843 has 2 divisors, whose sum is σ = 1989509844. Its totient is φ = 1989509842.

The previous prime is 1989509801. The next prime is 1989509897. The reversal of 1989509843 is 3489059891.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1989509843 - 2¹⁶ = 1989444307 is a prime.

It is not a weakly prime, because it can be changed into another prime (1989509443) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 994754921 + 994754922.

It is an arithmetic number, because the mean of its divisors is an integer number (994754922).

Almost surely, 2^1989509843 is an apocalyptic number.

1989509843 is a deficient number, since it is larger than the sum of its proper divisors (1).

1989509843 is an equidigital number, since it uses as much as digits as its factorization.

1989509843 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2799360, while the sum is 56.

The square root of 1989509843 is about 44603.9218342961. The cubic root of 1989509843 is about 1257.7143924188.

The spelling of 1989509843 in words is "one billion, nine hundred eighty-nine million, five hundred nine thousand, eight hundred forty-three".