66540871 has 2 divisors, whose sum is σ = 66540872. Its totient is φ = 66540870.

The previous prime is 66540857. The next prime is 66540883. The reversal of 66540871 is 17804566.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66540871 - 2⁷ = 66540743 is a prime.

It is equal to p_3926296 and since 66540871 and 3926296 have the same sum of digits, it is a Honaker prime.

It is a self number, because there is not a number n which added to its sum of digits gives 66540871.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66540821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33270435 + 33270436.

It is an arithmetic number, because the mean of its divisors is an integer number (33270436).

Almost surely, 2^66540871 is an apocalyptic number.

66540871 is a deficient number, since it is larger than the sum of its proper divisors (1).

66540871 is an equidigital number, since it uses as much as digits as its factorization.

66540871 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40320, while the sum is 37.

The square root of 66540871 is about 8157.2587920208. The cubic root of 66540871 is about 405.2249342381.

The spelling of 66540871 in words is "sixty-six million, five hundred forty thousand, eight hundred seventy-one".