1630778491 has 2 divisors, whose sum is σ = 1630778492. Its totient is φ = 1630778490.

The previous prime is 1630778447. The next prime is 1630778497. The reversal of 1630778491 is 1948770361.

It is a strong prime.

It is an emirp because it is prime and its reverse (1948770361) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1630778491 - 2⁹ = 1630777979 is a prime.

It is not a weakly prime, because it can be changed into another prime (1630778497) 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, 815389245 + 815389246.

It is an arithmetic number, because the mean of its divisors is an integer number (815389246).

Almost surely, 2^1630778491 is an apocalyptic number.

1630778491 is a deficient number, since it is larger than the sum of its proper divisors (1).

1630778491 is an equidigital number, since it uses as much as digits as its factorization.

1630778491 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 254016, while the sum is 46.

The square root of 1630778491 is about 40382.8984967647. The cubic root of 1630778491 is about 1177.0592508118.

The spelling of 1630778491 in words is "one billion, six hundred thirty million, seven hundred seventy-eight thousand, four hundred ninety-one".