19189661 has 2 divisors, whose sum is σ = 19189662. Its totient is φ = 19189660.

The previous prime is 19189631. The next prime is 19189663. The reversal of 19189661 is 16698191.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18541636 + 648025 = 4306^2 + 805^2 .

It is an emirp because it is prime and its reverse (16698191) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19189661 - 2¹⁴ = 19173277 is a prime.

Together with 19189663, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19189663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9594830 + 9594831.

It is an arithmetic number, because the mean of its divisors is an integer number (9594831).

Almost surely, 2^19189661 is an apocalyptic number.

It is an amenable number.

19189661 is a deficient number, since it is larger than the sum of its proper divisors (1).

19189661 is an equidigital number, since it uses as much as digits as its factorization.

19189661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 23328, while the sum is 41.

The square root of 19189661 is about 4380.6005296078. The cubic root of 19189661 is about 267.7251070469.

The spelling of 19189661 in words is "nineteen million, one hundred eighty-nine thousand, six hundred sixty-one".