2128217063281 has 3 divisors (see below), whose sum is σ = 2128218522123. Its totient is φ = 2128215604440.

The previous prime is 2128217063267. The next prime is 2128217063299. The reversal of 2128217063281 is 1823607128212.

The square root of 2128217063281 is 1458841.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 621509912881 + 1506707150400 = 788359^2 + 1227480^2 .

It is a de Polignac number, because none of the positive numbers 2^k-2128217063281 is a prime.

It is a super-2 number, since 2×2128217063281² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2128217063251) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 729421 + ... + 2188261.

It is an arithmetic number, because the mean of its divisors is an integer number (709406174041).

Almost surely, 2^{2128217063281} is an apocalyptic number.

2128217063281 is the 1458841-st square number.

2128217063281 is the 729421-st centered octagonal number.

It is an amenable number.

2128217063281 is a deficient number, since it is larger than the sum of its proper divisors (1458842).

2128217063281 is an frugal number, since it uses more digits than its factorization.

2128217063281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2917682 (or 1458841 counting only the distinct ones).

The product of its (nonzero) digits is 129024, while the sum is 43.

The spelling of 2128217063281 in words is "two trillion, one hundred twenty-eight billion, two hundred seventeen million, sixty-three thousand, two hundred eighty-one".