19655989 has 2 divisors, whose sum is σ = 19655990. Its totient is φ = 19655988.

The previous prime is 19655963. The next prime is 19656017. The reversal of 19655989 is 98955691.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13380964 + 6275025 = 3658^2 + 2505^2 .

It is a cyclic number.

It is not a de Polignac number, because 19655989 - 2⁵ = 19655957 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19655959) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9827994 + 9827995.

It is an arithmetic number, because the mean of its divisors is an integer number (9827995).

Almost surely, 2^19655989 is an apocalyptic number.

It is an amenable number.

19655989 is a deficient number, since it is larger than the sum of its proper divisors (1).

19655989 is an equidigital number, since it uses as much as digits as its factorization.

19655989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 874800, while the sum is 52.

The square root of 19655989 is about 4433.5075279061. The cubic root of 19655989 is about 269.8764363733.

The spelling of 19655989 in words is "nineteen million, six hundred fifty-five thousand, nine hundred eighty-nine".