16621823863261 has 2 divisors, whose sum is σ = 16621823863262. Its totient is φ = 16621823863260.

The previous prime is 16621823863199. The next prime is 16621823863273. The reversal of 16621823863261 is 16236832812661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12720136240900 + 3901687622361 = 3566530^2 + 1975269^2 .

It is a cyclic number.

It is not a de Polignac number, because 16621823863261 - 2⁷ = 16621823863133 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16621823813261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8310911931630 + 8310911931631.

It is an arithmetic number, because the mean of its divisors is an integer number (8310911931631).

Almost surely, 2^{16621823863261} is an apocalyptic number.

It is an amenable number.

16621823863261 is a deficient number, since it is larger than the sum of its proper divisors (1).

16621823863261 is an equidigital number, since it uses as much as digits as its factorization.

16621823863261 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5971968, while the sum is 55.

The spelling of 16621823863261 in words is "sixteen trillion, six hundred twenty-one billion, eight hundred twenty-three million, eight hundred sixty-three thousand, two hundred sixty-one".