65781493 has 2 divisors, whose sum is σ = 65781494. Its totient is φ = 65781492.

The previous prime is 65781479. The next prime is 65781497. The reversal of 65781493 is 39418756.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 65399569 + 381924 = 8087^2 + 618^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-65781493 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (65781497) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 32890746 + 32890747.

It is an arithmetic number, because the mean of its divisors is an integer number (32890747).

Almost surely, 2^65781493 is an apocalyptic number.

It is an amenable number.

65781493 is a deficient number, since it is larger than the sum of its proper divisors (1).

65781493 is an equidigital number, since it uses as much as digits as its factorization.

65781493 is an evil number, because the sum of its binary digits is even.

The product of its digits is 181440, while the sum is 43.

The square root of 65781493 is about 8110.5790792027. The cubic root of 65781493 is about 403.6775295745.

The spelling of 65781493 in words is "sixty-five million, seven hundred eighty-one thousand, four hundred ninety-three".