1664651249 has 2 divisors, whose sum is σ = 1664651250. Its totient is φ = 1664651248.

The previous prime is 1664651213. The next prime is 1664651267. The reversal of 1664651249 is 9421564661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1662600625 + 2050624 = 40775^2 + 1432^2 .

It is an emirp because it is prime and its reverse (9421564661) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1664651249 is a prime.

It is not a weakly prime, because it can be changed into another prime (1664651269) 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, 832325624 + 832325625.

It is an arithmetic number, because the mean of its divisors is an integer number (832325625).

Almost surely, 2^1664651249 is an apocalyptic number.

It is an amenable number.

1664651249 is a deficient number, since it is larger than the sum of its proper divisors (1).

1664651249 is an equidigital number, since it uses as much as digits as its factorization.

1664651249 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 311040, while the sum is 44.

The square root of 1664651249 is about 40800.1378551593. The cubic root of 1664651249 is about 1185.1530003566.

The spelling of 1664651249 in words is "one billion, six hundred sixty-four million, six hundred fifty-one thousand, two hundred forty-nine".