16212605561 has 2 divisors, whose sum is σ = 16212605562. Its totient is φ = 16212605560.

The previous prime is 16212605557. The next prime is 16212605569. The reversal of 16212605561 is 16550621261.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14052679936 + 2159925625 = 118544^2 + 46475^2 .

It is a cyclic number.

It is not a de Polignac number, because 16212605561 - 2² = 16212605557 is a prime.

It is not a weakly prime, because it can be changed into another prime (16212605569) 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, 8106302780 + 8106302781.

It is an arithmetic number, because the mean of its divisors is an integer number (8106302781).

Almost surely, 2^16212605561 is an apocalyptic number.

It is an amenable number.

16212605561 is a deficient number, since it is larger than the sum of its proper divisors (1).

16212605561 is an equidigital number, since it uses as much as digits as its factorization.

16212605561 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 21600, while the sum is 35.

It can be divided in two parts, 16 and 212605561, that multiplied together give a square (3401688976 = 58324²).

The spelling of 16212605561 in words is "sixteen billion, two hundred twelve million, six hundred five thousand, five hundred sixty-one".