1630720813 has 2 divisors, whose sum is σ = 1630720814. Its totient is φ = 1630720812.

The previous prime is 1630720811. The next prime is 1630720831. The reversal of 1630720813 is 3180270361.

Together with next prime (1630720831) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1574740489 + 55980324 = 39683^2 + 7482^2 .

It is a cyclic number.

It is not a de Polignac number, because 1630720813 - 2¹ = 1630720811 is a prime.

Together with 1630720811, 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 (1630720811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 815360406 + 815360407.

It is an arithmetic number, because the mean of its divisors is an integer number (815360407).

Almost surely, 2^1630720813 is an apocalyptic number.

It is an amenable number.

1630720813 is a deficient number, since it is larger than the sum of its proper divisors (1).

1630720813 is an equidigital number, since it uses as much as digits as its factorization.

1630720813 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6048, while the sum is 31.

The square root of 1630720813 is about 40382.1843515182. The cubic root of 1630720813 is about 1177.0453737537.

The spelling of 1630720813 in words is "one billion, six hundred thirty million, seven hundred twenty thousand, eight hundred thirteen".