208402686673261 has 2 divisors, whose sum is σ = 208402686673262. Its totient is φ = 208402686673260.

The previous prime is 208402686673249. The next prime is 208402686673297. The reversal of 208402686673261 is 162376686204802.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 206509258384900 + 1893428288361 = 14370430^2 + 1376019^2 .

It is a cyclic number.

It is not a de Polignac number, because 208402686673261 - 2¹¹ = 208402686671213 is a prime.

It is a super-2 number, since 2×208402686673261² (a number of 29 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 208402686673261.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (208402686673201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 104201343336630 + 104201343336631.

It is an arithmetic number, because the mean of its divisors is an integer number (104201343336631).

Almost surely, 2^{208402686673261} is an apocalyptic number.

It is an amenable number.

208402686673261 is a deficient number, since it is larger than the sum of its proper divisors (1).

208402686673261 is an equidigital number, since it uses as much as digits as its factorization.

208402686673261 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 55738368, while the sum is 61.

The spelling of 208402686673261 in words is "two hundred eight trillion, four hundred two billion, six hundred eighty-six million, six hundred seventy-three thousand, two hundred sixty-one".