819990649 has 2 divisors, whose sum is σ = 819990650. Its totient is φ = 819990648.

The previous prime is 819990643. The next prime is 819990653. The reversal of 819990649 is 946099918.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 522945424 + 297045225 = 22868^2 + 17235^2 .

It is a cyclic number.

It is not a de Polignac number, because 819990649 - 2⁹ = 819990137 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 819990649.

It is not a weakly prime, because it can be changed into another prime (819990643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 409995324 + 409995325.

It is an arithmetic number, because the mean of its divisors is an integer number (409995325).

Almost surely, 2^819990649 is an apocalyptic number.

It is an amenable number.

819990649 is a deficient number, since it is larger than the sum of its proper divisors (1).

819990649 is an equidigital number, since it uses as much as digits as its factorization.

819990649 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1259712, while the sum is 55.

The square root of 819990649 is about 28635.4788505448. The cubic root of 819990649 is about 935.9866043965.

The spelling of 819990649 in words is "eight hundred nineteen million, nine hundred ninety thousand, six hundred forty-nine".