1981969289 has 2 divisors, whose sum is σ = 1981969290. Its totient is φ = 1981969288.

The previous prime is 1981969261. The next prime is 1981969307. The reversal of 1981969289 is 9829691891.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1264158025 + 717811264 = 35555^2 + 26792^2 .

It is a cyclic number.

It is not a de Polignac number, because 1981969289 - 2¹⁶ = 1981903753 is a prime.

It is not a weakly prime, because it can be changed into another prime (1981969219) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 990984644 + 990984645.

It is an arithmetic number, because the mean of its divisors is an integer number (990984645).

Almost surely, 2^1981969289 is an apocalyptic number.

It is an amenable number.

1981969289 is a deficient number, since it is larger than the sum of its proper divisors (1).

1981969289 is an equidigital number, since it uses as much as digits as its factorization.

1981969289 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5038848, while the sum is 62.

The square root of 1981969289 is about 44519.3136627240. The cubic root of 1981969289 is about 1256.1234024915.

The spelling of 1981969289 in words is "one billion, nine hundred eighty-one million, nine hundred sixty-nine thousand, two hundred eighty-nine".