68191993 has 2 divisors, whose sum is σ = 68191994. Its totient is φ = 68191992.

The previous prime is 68191951. The next prime is 68192009. The reversal of 68191993 is 39919186.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 62678889 + 5513104 = 7917^2 + 2348^2 .

It is a cyclic number.

It is not a de Polignac number, because 68191993 - 2¹⁷ = 68060921 is a prime.

It is not a weakly prime, because it can be changed into another prime (68191493) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34095996 + 34095997.

It is an arithmetic number, because the mean of its divisors is an integer number (34095997).

Almost surely, 2^68191993 is an apocalyptic number.

It is an amenable number.

68191993 is a deficient number, since it is larger than the sum of its proper divisors (1).

68191993 is an equidigital number, since it uses as much as digits as its factorization.

68191993 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 104976, while the sum is 46.

The square root of 68191993 is about 8257.8443313010. The cubic root of 68191993 is about 408.5492909944.

The spelling of 68191993 in words is "sixty-eight million, one hundred ninety-one thousand, nine hundred ninety-three".