1656664771 has 4 divisors (see below), whose sum is σ = 1656764200. Its totient is φ = 1656565344.

The previous prime is 1656664733. The next prime is 1656664783. The reversal of 1656664771 is 1774666561.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1656664771 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1656664271) 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 in 3 ways as a sum of consecutive naturals, for example, 17961 + ... + 60298.

It is an arithmetic number, because the mean of its divisors is an integer number (414191050).

Almost surely, 2^1656664771 is an apocalyptic number.

1656664771 is a deficient number, since it is larger than the sum of its proper divisors (99429).

1656664771 is an equidigital number, since it uses as much as digits as its factorization.

1656664771 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99428.

The product of its digits is 1270080, while the sum is 49.

The square root of 1656664771 is about 40702.1470072526. The cubic root of 1656664771 is about 1183.2546295778.

The spelling of 1656664771 in words is "one billion, six hundred fifty-six million, six hundred sixty-four thousand, seven hundred seventy-one".