19561189 has 2 divisors, whose sum is σ = 19561190. Its totient is φ = 19561188.

The previous prime is 19561121. The next prime is 19561193. The reversal of 19561189 is 98116591.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12496225 + 7064964 = 3535^2 + 2658^2 .

It is an emirp because it is prime and its reverse (98116591) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19561189 - 2¹³ = 19552997 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19568189) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9780594 + 9780595.

It is an arithmetic number, because the mean of its divisors is an integer number (9780595).

Almost surely, 2^19561189 is an apocalyptic number.

It is an amenable number.

19561189 is a deficient number, since it is larger than the sum of its proper divisors (1).

19561189 is an equidigital number, since it uses as much as digits as its factorization.

19561189 is an evil number, because the sum of its binary digits is even.

The product of its digits is 19440, while the sum is 40.

The square root of 19561189 is about 4422.8032965530. The cubic root of 19561189 is about 269.4418694605.

The spelling of 19561189 in words is "nineteen million, five hundred sixty-one thousand, one hundred eighty-nine".