1188406561 has 2 divisors, whose sum is σ = 1188406562. Its totient is φ = 1188406560.

The previous prime is 1188406553. The next prime is 1188406577. The reversal of 1188406561 is 1656048811.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1074856225 + 113550336 = 32785^2 + 10656^2 .

It is an emirp because it is prime and its reverse (1656048811) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1188406561 - 2³ = 1188406553 is a prime.

It is not a weakly prime, because it can be changed into another prime (1188406511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 594203280 + 594203281.

It is an arithmetic number, because the mean of its divisors is an integer number (594203281).

Almost surely, 2^1188406561 is an apocalyptic number.

It is an amenable number.

1188406561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1188406561 is an equidigital number, since it uses as much as digits as its factorization.

1188406561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 46080, while the sum is 40.

The square root of 1188406561 is about 34473.2731402169. The cubic root of 1188406561 is about 1059.2253034808.

The spelling of 1188406561 in words is "one billion, one hundred eighty-eight million, four hundred six thousand, five hundred sixty-one".