67666639 has 2 divisors, whose sum is σ = 67666640. Its totient is φ = 67666638.

The previous prime is 67666607. The next prime is 67666691. The reversal of 67666639 is 93666676.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 67666639 - 2⁵ = 67666607 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 67666592 and 67666601.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (67660639) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33833319 + 33833320.

It is an arithmetic number, because the mean of its divisors is an integer number (33833320).

Almost surely, 2^67666639 is an apocalyptic number.

67666639 is a deficient number, since it is larger than the sum of its proper divisors (1).

67666639 is an equidigital number, since it uses as much as digits as its factorization.

67666639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1469664, while the sum is 49.

The square root of 67666639 is about 8225.9734378370. The cubic root of 67666639 is about 407.4974248021.

The spelling of 67666639 in words is "sixty-seven million, six hundred sixty-six thousand, six hundred thirty-nine".