1813967993 has 2 divisors, whose sum is σ = 1813967994. Its totient is φ = 1813967992.

The previous prime is 1813967989. The next prime is 1813968001. The reversal of 1813967993 is 3997693181.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1779827344 + 34140649 = 42188^2 + 5843^2 .

It is a cyclic number.

It is not a de Polignac number, because 1813967993 - 2² = 1813967989 is a prime.

It is not a weakly prime, because it can be changed into another prime (1813967593) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 906983996 + 906983997.

It is an arithmetic number, because the mean of its divisors is an integer number (906983997).

Almost surely, 2^1813967993 is an apocalyptic number.

It is an amenable number.

1813967993 is a deficient number, since it is larger than the sum of its proper divisors (1).

1813967993 is an equidigital number, since it uses as much as digits as its factorization.

1813967993 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2204496, while the sum is 56.

The square root of 1813967993 is about 42590.7031287346. The cubic root of 1813967993 is about 1219.5788192725.

The spelling of 1813967993 in words is "one billion, eight hundred thirteen million, nine hundred sixty-seven thousand, nine hundred ninety-three".