209999852638481 has 2 divisors, whose sum is σ = 209999852638482. Its totient is φ = 209999852638480.

The previous prime is 209999852638469. The next prime is 209999852638483. The reversal of 209999852638481 is 184836258999902.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 203328092787856 + 6671759850625 = 14259316^2 + 2582975^2 .

It is a cyclic number.

It is not a de Polignac number, because 209999852638481 - 2¹⁴ = 209999852622097 is a prime.

It is a super-2 number, since 2×209999852638481² (a number of 29 digits) contains 22 as substring.

Together with 209999852638483, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 209999852638481.

It is not a weakly prime, because it can be changed into another prime (209999852638483) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104999926319240 + 104999926319241.

It is an arithmetic number, because the mean of its divisors is an integer number (104999926319241).

Almost surely, 2^{209999852638481} is an apocalyptic number.

It is an amenable number.

209999852638481 is a deficient number, since it is larger than the sum of its proper divisors (1).

209999852638481 is an equidigital number, since it uses as much as digits as its factorization.

209999852638481 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4837294080, while the sum is 83.

The spelling of 209999852638481 in words is "two hundred nine trillion, nine hundred ninety-nine billion, eight hundred fifty-two million, six hundred thirty-eight thousand, four hundred eighty-one".