66748639 has 2 divisors, whose sum is σ = 66748640. Its totient is φ = 66748638.

The previous prime is 66748631. The next prime is 66748687. The reversal of 66748639 is 93684766.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66748639 - 2³ = 66748631 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 66748592 and 66748601.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66748631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33374319 + 33374320.

It is an arithmetic number, because the mean of its divisors is an integer number (33374320).

Almost surely, 2^66748639 is an apocalyptic number.

66748639 is a deficient number, since it is larger than the sum of its proper divisors (1).

66748639 is an equidigital number, since it uses as much as digits as its factorization.

66748639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1306368, while the sum is 49.

The square root of 66748639 is about 8169.9840269122. The cubic root of 66748639 is about 405.6462557326.

The spelling of 66748639 in words is "sixty-six million, seven hundred forty-eight thousand, six hundred thirty-nine".