166642571 has 2 divisors, whose sum is σ = 166642572. Its totient is φ = 166642570.

The previous prime is 166642519. The next prime is 166642591. The reversal of 166642571 is 175246661.

It is a strong prime.

It is an emirp because it is prime and its reverse (175246661) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166642571 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (166642591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83321285 + 83321286.

It is an arithmetic number, because the mean of its divisors is an integer number (83321286).

Almost surely, 2^166642571 is an apocalyptic number.

166642571 is a deficient number, since it is larger than the sum of its proper divisors (1).

166642571 is an equidigital number, since it uses as much as digits as its factorization.

166642571 is an evil number, because the sum of its binary digits is even.

The product of its digits is 60480, while the sum is 38.

The square root of 166642571 is about 12909.0112324686. The cubic root of 166642571 is about 550.2946861582.

The spelling of 166642571 in words is "one hundred sixty-six million, six hundred forty-two thousand, five hundred seventy-one".