193681993 has 2 divisors, whose sum is σ = 193681994. Its totient is φ = 193681992.

The previous prime is 193681963. The next prime is 193682023. The reversal of 193681993 is 399186391.

193681993 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a balanced prime because it is at equal distance from previous prime (193681963) and next prime (193682023).

It can be written as a sum of positive squares in only one way, i.e., 134745664 + 58936329 = 11608^2 + 7677^2 .

It is an emirp because it is prime and its reverse (399186391) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-193681993 is a prime.

It is not a weakly prime, because it can be changed into another prime (193681913) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 96840996 + 96840997.

It is an arithmetic number, because the mean of its divisors is an integer number (96840997).

Almost surely, 2^193681993 is an apocalyptic number.

It is an amenable number.

193681993 is a deficient number, since it is larger than the sum of its proper divisors (1).

193681993 is an equidigital number, since it uses as much as digits as its factorization.

193681993 is an evil number, because the sum of its binary digits is even.

The product of its digits is 314928, while the sum is 49.

The square root of 193681993 is about 13916.9678091170. The cubic root of 193681993 is about 578.5795532322.

The spelling of 193681993 in words is "one hundred ninety-three million, six hundred eighty-one thousand, nine hundred ninety-three".