6553390081681 has 3 divisors (see below), whose sum is σ = 6553392641641. Its totient is φ = 6553387521722.

The previous prime is 6553390081631. The next prime is 6553390081687. The reversal of 6553390081681 is 1861800933556.

The square root of 6553390081681 is 2559959.

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 is not a de Polignac number, because 6553390081681 - 2¹⁷ = 6553389950609 is a prime.

It is a super-2 number, since 2×6553390081681² (a number of 26 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6553390081687) 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, 1279980 + ... + 3839938.

Almost surely, 2^{6553390081681} is an apocalyptic number.

6553390081681 is the 2559959-th square number.

6553390081681 is the 1279980-th centered octagonal number.

It is an amenable number.

6553390081681 is a deficient number, since it is larger than the sum of its proper divisors (2559960).

6553390081681 is an frugal number, since it uses more digits than its factorization.

6553390081681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5119918 (or 2559959 counting only the distinct ones).

The product of its (nonzero) digits is 4665600, while the sum is 55.

The spelling of 6553390081681 in words is "six trillion, five hundred fifty-three billion, three hundred ninety million, eighty-one thousand, six hundred eighty-one".