1666616249 has 2 divisors, whose sum is σ = 1666616250. Its totient is φ = 1666616248.

The previous prime is 1666616209. The next prime is 1666616261. The reversal of 1666616249 is 9426166661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 926776249 + 739840000 = 30443^2 + 27200^2 .

It is a cyclic number.

It is not a de Polignac number, because 1666616249 - 2²⁴ = 1649839033 is a prime.

It is not a weakly prime, because it can be changed into another prime (1666616209) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833308124 + 833308125.

It is an arithmetic number, because the mean of its divisors is an integer number (833308125).

Almost surely, 2^1666616249 is an apocalyptic number.

It is an amenable number.

1666616249 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666616249 is an equidigital number, since it uses as much as digits as its factorization.

1666616249 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 559872, while the sum is 47.

The square root of 1666616249 is about 40824.2115539296. The cubic root of 1666616249 is about 1185.6191460254.

The spelling of 1666616249 in words is "one billion, six hundred sixty-six million, six hundred sixteen thousand, two hundred forty-nine".