216655132321 has 4 divisors (see below), whose sum is σ = 216656167572. Its totient is φ = 216654097072.

The previous prime is 216655132301. The next prime is 216655132381. The reversal of 216655132321 is 123231556612.

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 2 ways, for example, as 36696766096 + 179958366225 = 191564^2 + 424215^2 .

It is a cyclic number.

It is not a de Polignac number, because 216655132321 - 2³¹ = 214507648673 is a prime.

It is a super-2 number, since 2×216655132321² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (216655132301) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 80866 + ... + 663211.

It is an arithmetic number, because the mean of its divisors is an integer number (54164041893).

Almost surely, 2^216655132321 is an apocalyptic number.

It is an amenable number.

216655132321 is a deficient number, since it is larger than the sum of its proper divisors (1035251).

216655132321 is an equidigital number, since it uses as much as digits as its factorization.

216655132321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1035250.

The product of its digits is 64800, while the sum is 37.

Adding to 216655132321 its reverse (123231556612), we get a palindrome (339886688933).

The spelling of 216655132321 in words is "two hundred sixteen billion, six hundred fifty-five million, one hundred thirty-two thousand, three hundred twenty-one".