19980689 has 2 divisors, whose sum is σ = 19980690. Its totient is φ = 19980688.

The previous prime is 19980683. The next prime is 19980707. The reversal of 19980689 is 98608991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15737089 + 4243600 = 3967^2 + 2060^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19980689 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (19980683) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9990344 + 9990345.

It is an arithmetic number, because the mean of its divisors is an integer number (9990345).

Almost surely, 2^19980689 is an apocalyptic number.

It is an amenable number.

19980689 is a deficient number, since it is larger than the sum of its proper divisors (1).

19980689 is an equidigital number, since it uses as much as digits as its factorization.

19980689 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 279936, while the sum is 50.

The square root of 19980689 is about 4469.9763981480. The cubic root of 19980689 is about 271.3543699955.

The spelling of 19980689 in words is "nineteen million, nine hundred eighty thousand, six hundred eighty-nine".