1166510221 has 2 divisors, whose sum is σ = 1166510222. Its totient is φ = 1166510220.

The previous prime is 1166510173. The next prime is 1166510269. The reversal of 1166510221 is 1220156611.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (1166510173) and next prime (1166510269).

It can be written as a sum of positive squares in only one way, i.e., 1096536996 + 69973225 = 33114^2 + 8365^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1166510221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1166511221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 583255110 + 583255111.

It is an arithmetic number, because the mean of its divisors is an integer number (583255111).

Almost surely, 2^1166510221 is an apocalyptic number.

It is an amenable number.

1166510221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1166510221 is an equidigital number, since it uses as much as digits as its factorization.

1166510221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 720, while the sum is 25.

The square root of 1166510221 is about 34154.2123463563. The cubic root of 1166510221 is about 1052.6795419303.

Adding to 1166510221 its reverse (1220156611), we get a palindrome (2386666832).

The spelling of 1166510221 in words is "one billion, one hundred sixty-six million, five hundred ten thousand, two hundred twenty-one".