66790639 has 2 divisors, whose sum is σ = 66790640. Its totient is φ = 66790638.

The previous prime is 66790631. The next prime is 66790649. The reversal of 66790639 is 93609766.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66790639 - 2³ = 66790631 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66790631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33395319 + 33395320.

It is an arithmetic number, because the mean of its divisors is an integer number (33395320).

Almost surely, 2^66790639 is an apocalyptic number.

66790639 is a deficient number, since it is larger than the sum of its proper divisors (1).

66790639 is an equidigital number, since it uses as much as digits as its factorization.

66790639 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 367416, while the sum is 46.

The square root of 66790639 is about 8172.5540071632. The cubic root of 66790639 is about 405.7313189930.

The spelling of 66790639 in words is "sixty-six million, seven hundred ninety thousand, six hundred thirty-nine".