66660871 has 2 divisors, whose sum is σ = 66660872. Its totient is φ = 66660870.

The previous prime is 66660863. The next prime is 66660907. The reversal of 66660871 is 17806666.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66660871 - 2³ = 66660863 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66660071) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33330435 + 33330436.

It is an arithmetic number, because the mean of its divisors is an integer number (33330436).

Almost surely, 2^66660871 is an apocalyptic number.

66660871 is a deficient number, since it is larger than the sum of its proper divisors (1).

66660871 is an equidigital number, since it uses as much as digits as its factorization.

66660871 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72576, while the sum is 40.

The square root of 66660871 is about 8164.6108909121. The cubic root of 66660871 is about 405.4683825593.

Subtracting from 66660871 its sum of digits (40), we obtain a triangular number (66660831 = T₁₁₅₄₆).

The spelling of 66660871 in words is "sixty-six million, six hundred sixty thousand, eight hundred seventy-one".