16205530563661 has 2 divisors, whose sum is σ = 16205530563662. Its totient is φ = 16205530563660.

The previous prime is 16205530563619. The next prime is 16205530563881. The reversal of 16205530563661 is 16636503550261.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 13880915004100 + 2324615559561 = 3725710^2 + 1524669^2 .

It is a cyclic number.

It is not a de Polignac number, because 16205530563661 - 2²³ = 16205522175053 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16205530564661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8102765281830 + 8102765281831.

It is an arithmetic number, because the mean of its divisors is an integer number (8102765281831).

Almost surely, 2^{16205530563661} is an apocalyptic number.

It is an amenable number.

16205530563661 is a deficient number, since it is larger than the sum of its proper divisors (1).

16205530563661 is an equidigital number, since it uses as much as digits as its factorization.

16205530563661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2916000, while the sum is 49.

The spelling of 16205530563661 in words is "sixteen trillion, two hundred five billion, five hundred thirty million, five hundred sixty-three thousand, six hundred sixty-one".