16205664641 has 2 divisors, whose sum is σ = 16205664642. Its totient is φ = 16205664640.

The previous prime is 16205664617. The next prime is 16205664649. The reversal of 16205664641 is 14646650261.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11050424641 + 5155240000 = 105121^2 + 71800^2 .

It is a cyclic number.

It is not a de Polignac number, because 16205664641 - 2⁶ = 16205664577 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (16205664649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8102832320 + 8102832321.

It is an arithmetic number, because the mean of its divisors is an integer number (8102832321).

Almost surely, 2^16205664641 is an apocalyptic number.

It is an amenable number.

16205664641 is a deficient number, since it is larger than the sum of its proper divisors (1).

16205664641 is an equidigital number, since it uses as much as digits as its factorization.

16205664641 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 207360, while the sum is 41.

The spelling of 16205664641 in words is "sixteen billion, two hundred five million, six hundred sixty-four thousand, six hundred forty-one".