1994635813 has 2 divisors, whose sum is σ = 1994635814. Its totient is φ = 1994635812.

The previous prime is 1994635793. The next prime is 1994635837. The reversal of 1994635813 is 3185364991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1976513764 + 18122049 = 44458^2 + 4257^2 .

It is a cyclic number.

It is not a de Polignac number, because 1994635813 - 2⁹ = 1994635301 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1994635913) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 997317906 + 997317907.

It is an arithmetic number, because the mean of its divisors is an integer number (997317907).

Almost surely, 2^1994635813 is an apocalyptic number.

It is an amenable number.

1994635813 is a deficient number, since it is larger than the sum of its proper divisors (1).

1994635813 is an equidigital number, since it uses as much as digits as its factorization.

1994635813 is an evil number, because the sum of its binary digits is even.

The product of its digits is 699840, while the sum is 49.

The square root of 1994635813 is about 44661.3458485075. The cubic root of 1994635813 is about 1258.7936326610.

The spelling of 1994635813 in words is "one billion, nine hundred ninety-four million, six hundred thirty-five thousand, eight hundred thirteen".