68639 has 2 divisors, whose sum is σ = 68640. Its totient is φ = 68638.

The previous prime is 68633. The next prime is 68659. The reversal of 68639 is 93686.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-68639 is a prime.

It is a super-2 number, since 2×68639² = 9422624642, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (68633) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34319 + 34320.

It is an arithmetic number, because the mean of its divisors is an integer number (34320).

2⁶⁸⁶³⁹ is an apocalyptic number.

68639 is a deficient number, since it is larger than the sum of its proper divisors (1).

68639 is an equidigital number, since it uses as much as digits as its factorization.

68639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7776, while the sum is 32.

The square root of 68639 is about 261.9904578415. The cubic root of 68639 is about 40.9440044634.

It can be divided in two parts, 68 and 639, that added together give a palindrome (707).

The spelling of 68639 in words is "sixty-eight thousand, six hundred thirty-nine".