1649243509 has 2 divisors, whose sum is σ = 1649243510. Its totient is φ = 1649243508.

The previous prime is 1649243507. The next prime is 1649243549. The reversal of 1649243509 is 9053429461.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1356080625 + 293162884 = 36825^2 + 17122^2 .

It is a cyclic number.

It is not a de Polignac number, because 1649243509 - 2¹ = 1649243507 is a prime.

Together with 1649243507, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1649243501) 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, 824621754 + 824621755.

It is an arithmetic number, because the mean of its divisors is an integer number (824621755).

Almost surely, 2^1649243509 is an apocalyptic number.

It is an amenable number.

1649243509 is a deficient number, since it is larger than the sum of its proper divisors (1).

1649243509 is an equidigital number, since it uses as much as digits as its factorization.

1649243509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 233280, while the sum is 43.

The square root of 1649243509 is about 40610.8791951122. The cubic root of 1649243509 is about 1181.4851330625.

The spelling of 1649243509 in words is "one billion, six hundred forty-nine million, two hundred forty-three thousand, five hundred nine".