1189005661 has 2 divisors, whose sum is σ = 1189005662. Its totient is φ = 1189005660.

The previous prime is 1189005659. The next prime is 1189005667. The reversal of 1189005661 is 1665009811.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 795578436 + 393427225 = 28206^2 + 19835^2 .

It is an emirp because it is prime and its reverse (1665009811) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1189005661 - 2¹ = 1189005659 is a prime.

Together with 1189005659, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 1189005661.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1189005667) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 594502830 + 594502831.

It is an arithmetic number, because the mean of its divisors is an integer number (594502831).

Almost surely, 2^1189005661 is an apocalyptic number.

It is an amenable number.

1189005661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1189005661 is an equidigital number, since it uses as much as digits as its factorization.

1189005661 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 37.

The square root of 1189005661 is about 34481.9613856289. The cubic root of 1189005661 is about 1059.4032659432.

The spelling of 1189005661 in words is "one billion, one hundred eighty-nine million, five thousand, six hundred sixty-one".