1166554561 has 2 divisors, whose sum is σ = 1166554562. Its totient is φ = 1166554560.

The previous prime is 1166554559. The next prime is 1166554567. The reversal of 1166554561 is 1654556611.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1098591025 + 67963536 = 33145^2 + 8244^2 .

It is a cyclic number.

It is not a de Polignac number, because 1166554561 - 2¹ = 1166554559 is a prime.

Together with 1166554559, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1166554567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 583277280 + 583277281.

It is an arithmetic number, because the mean of its divisors is an integer number (583277281).

Almost surely, 2^1166554561 is an apocalyptic number.

It is an amenable number.

1166554561 is a deficient number, since it is larger than the sum of its proper divisors (1).

1166554561 is an equidigital number, since it uses as much as digits as its factorization.

1166554561 is an evil number, because the sum of its binary digits is even.

The product of its digits is 108000, while the sum is 40.

The square root of 1166554561 is about 34154.8614548500. The cubic root of 1166554561 is about 1052.6928794958.

The spelling of 1166554561 in words is "one billion, one hundred sixty-six million, five hundred fifty-four thousand, five hundred sixty-one".