68139817 has 2 divisors, whose sum is σ = 68139818. Its totient is φ = 68139816.

The previous prime is 68139811. The next prime is 68139839. The reversal of 68139817 is 71893186.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 65755881 + 2383936 = 8109^2 + 1544^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-68139817 is a prime.

It is a super-3 number, since 3×68139817³ (a number of 24 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (68139811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34069908 + 34069909.

It is an arithmetic number, because the mean of its divisors is an integer number (34069909).

Almost surely, 2^68139817 is an apocalyptic number.

It is an amenable number.

68139817 is a deficient number, since it is larger than the sum of its proper divisors (1).

68139817 is an equidigital number, since it uses as much as digits as its factorization.

68139817 is an evil number, because the sum of its binary digits is even.

The product of its digits is 72576, while the sum is 43.

The square root of 68139817 is about 8254.6845487880. The cubic root of 68139817 is about 408.4450661148.

The spelling of 68139817 in words is "sixty-eight million, one hundred thirty-nine thousand, eight hundred seventeen".