9877655543221 has 2 divisors, whose sum is σ = 9877655543222. Its totient is φ = 9877655543220.

The previous prime is 9877655543219. The next prime is 9877655543237. The reversal of 9877655543221 is 1223455567789.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5102945460900 + 4774710082321 = 2258970^2 + 2185111^2 .

It is a cyclic number.

It is not a de Polignac number, because 9877655543221 - 2¹ = 9877655543219 is a prime.

Together with 9877655543219, it forms a pair of twin primes.

It is a nialpdrome in base 10.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9877655543251) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4938827771610 + 4938827771611.

It is an arithmetic number, because the mean of its divisors is an integer number (4938827771611).

Almost surely, 2^{9877655543221} is an apocalyptic number.

It is an amenable number.

9877655543221 is a deficient number, since it is larger than the sum of its proper divisors (1).

9877655543221 is an equidigital number, since it uses as much as digits as its factorization.

9877655543221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 127008000, while the sum is 64.

The spelling of 9877655543221 in words is "nine trillion, eight hundred seventy-seven billion, six hundred fifty-five million, five hundred forty-three thousand, two hundred twenty-one".