66401239 has 2 divisors, whose sum is σ = 66401240. Its totient is φ = 66401238.

The previous prime is 66401227. The next prime is 66401243. The reversal of 66401239 is 93210466.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66401239 - 2²¹ = 64304087 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 66401239.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66401249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33200619 + 33200620.

It is an arithmetic number, because the mean of its divisors is an integer number (33200620).

Almost surely, 2^66401239 is an apocalyptic number.

66401239 is a deficient number, since it is larger than the sum of its proper divisors (1).

66401239 is an equidigital number, since it uses as much as digits as its factorization.

66401239 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7776, while the sum is 31.

The square root of 66401239 is about 8148.6955397781. The cubic root of 66401239 is about 404.9412890558.

The spelling of 66401239 in words is "sixty-six million, four hundred one thousand, two hundred thirty-nine".