1189105661 has 2 divisors, whose sum is σ = 1189105662. Its totient is φ = 1189105660.

The previous prime is 1189105651. The next prime is 1189105679. The reversal of 1189105661 is 1665019811.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1160696761 + 28408900 = 34069^2 + 5330^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1189105661 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1189105601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 594552830 + 594552831.

It is an arithmetic number, because the mean of its divisors is an integer number (594552831).

Almost surely, 2^1189105661 is an apocalyptic number.

It is an amenable number.

1189105661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1189105661 is an equidigital number, since it uses as much as digits as its factorization.

1189105661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12960, while the sum is 38.

The square root of 1189105661 is about 34483.4113886663. The cubic root of 1189105661 is about 1059.4329650888.

The spelling of 1189105661 in words is "one billion, one hundred eighty-nine million, one hundred five thousand, six hundred sixty-one".