68591639 has 2 divisors, whose sum is σ = 68591640. Its totient is φ = 68591638.

The previous prime is 68591597. The next prime is 68591693. The reversal of 68591639 is 93619586.

Together with next prime (68591693) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-68591639 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 68591593 and 68591602.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (68591839) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34295819 + 34295820.

It is an arithmetic number, because the mean of its divisors is an integer number (34295820).

Almost surely, 2^68591639 is an apocalyptic number.

68591639 is a deficient number, since it is larger than the sum of its proper divisors (1).

68591639 is an equidigital number, since it uses as much as digits as its factorization.

68591639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 349920, while the sum is 47.

The square root of 68591639 is about 8282.0069427645. The cubic root of 68591639 is about 409.3458515773.

The spelling of 68591639 in words is "sixty-eight million, five hundred ninety-one thousand, six hundred thirty-nine".