1664664571 has 2 divisors, whose sum is σ = 1664664572. Its totient is φ = 1664664570.

The previous prime is 1664664569. The next prime is 1664664587. The reversal of 1664664571 is 1754664661.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1664664571 - 2¹ = 1664664569 is a prime.

It is a super-2 number, since 2×1664664571² = 5542216267885228082, which contains 22 as substring.

Together with 1664664569, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (1664664541) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 832332285 + 832332286.

It is an arithmetic number, because the mean of its divisors is an integer number (832332286).

Almost surely, 2^1664664571 is an apocalyptic number.

1664664571 is a deficient number, since it is larger than the sum of its proper divisors (1).

1664664571 is an equidigital number, since it uses as much as digits as its factorization.

1664664571 is an evil number, because the sum of its binary digits is even.

The product of its digits is 725760, while the sum is 46.

The square root of 1664664571 is about 40800.3011140849. The cubic root of 1664664571 is about 1185.1561618929.

The spelling of 1664664571 in words is "one billion, six hundred sixty-four million, six hundred sixty-four thousand, five hundred seventy-one".