66540671 has 2 divisors, whose sum is σ = 66540672. Its totient is φ = 66540670.

The previous prime is 66540667. The next prime is 66540697. The reversal of 66540671 is 17604566.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66540671 - 2² = 66540667 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66540871) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33270335 + 33270336.

It is an arithmetic number, because the mean of its divisors is an integer number (33270336).

Almost surely, 2^66540671 is an apocalyptic number.

66540671 is a deficient number, since it is larger than the sum of its proper divisors (1).

66540671 is an equidigital number, since it uses as much as digits as its factorization.

66540671 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 30240, while the sum is 35.

The square root of 66540671 is about 8157.2465329914. The cubic root of 66540671 is about 405.2245282466.

The spelling of 66540671 in words is "sixty-six million, five hundred forty thousand, six hundred seventy-one".