66431611 has 2 divisors, whose sum is σ = 66431612. Its totient is φ = 66431610.

The previous prime is 66431609. The next prime is 66431669. The reversal of 66431611 is 11613466.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66431611 - 2¹ = 66431609 is a prime.

Together with 66431609, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 66431611.

It is not a weakly prime, because it can be changed into another prime (66431671) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33215805 + 33215806.

It is an arithmetic number, because the mean of its divisors is an integer number (33215806).

Almost surely, 2^66431611 is an apocalyptic number.

66431611 is a deficient number, since it is larger than the sum of its proper divisors (1).

66431611 is an equidigital number, since it uses as much as digits as its factorization.

66431611 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2592, while the sum is 28.

The square root of 66431611 is about 8150.5589378889. The cubic root of 66431611 is about 405.0030198423.

The spelling of 66431611 in words is "sixty-six million, four hundred thirty-one thousand, six hundred eleven".