16571927821 has 2 divisors, whose sum is σ = 16571927822. Its totient is φ = 16571927820.

The previous prime is 16571927819. The next prime is 16571927833. The reversal of 16571927821 is 12872917561.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16309844100 + 262083721 = 127710^2 + 16189^2 .

It is a cyclic number.

It is not a de Polignac number, because 16571927821 - 2¹ = 16571927819 is a prime.

Together with 16571927819, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16571927861) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8285963910 + 8285963911.

It is an arithmetic number, because the mean of its divisors is an integer number (8285963911).

Almost surely, 2^16571927821 is an apocalyptic number.

It is an amenable number.

16571927821 is a deficient number, since it is larger than the sum of its proper divisors (1).

16571927821 is an equidigital number, since it uses as much as digits as its factorization.

16571927821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 423360, while the sum is 49.

The spelling of 16571927821 in words is "sixteen billion, five hundred seventy-one million, nine hundred twenty-seven thousand, eight hundred twenty-one".