9919781393 has 2 divisors, whose sum is σ = 9919781394. Its totient is φ = 9919781392.

The previous prime is 9919781381. The next prime is 9919781429. The reversal of 9919781393 is 3931879199.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5809945729 + 4109835664 = 76223^2 + 64108^2 .

It is a cyclic number.

It is not a de Polignac number, because 9919781393 - 2⁶ = 9919781329 is a prime.

It is not a weakly prime, because it can be changed into another prime (9919781303) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4959890696 + 4959890697.

It is an arithmetic number, because the mean of its divisors is an integer number (4959890697).

Almost surely, 2^9919781393 is an apocalyptic number.

It is an amenable number.

9919781393 is a deficient number, since it is larger than the sum of its proper divisors (1).

9919781393 is an equidigital number, since it uses as much as digits as its factorization.

9919781393 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3306744, while the sum is 59.

The square root of 9919781393 is about 99598.0993443148. The cubic root of 9919781393 is about 2148.6583584209.

The spelling of 9919781393 in words is "nine billion, nine hundred nineteen million, seven hundred eighty-one thousand, three hundred ninety-three".