21555320341 has 2 divisors, whose sum is σ = 21555320342. Its totient is φ = 21555320340.

The previous prime is 21555320329. The next prime is 21555320363. The reversal of 21555320341 is 14302355512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18751194225 + 2804126116 = 136935^2 + 52954^2 .

It is a cyclic number.

It is not a de Polignac number, because 21555320341 - 2⁹ = 21555319829 is a prime.

It is a super-3 number, since 3×21555320341³ (a number of 32 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21555320041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10777660170 + 10777660171.

It is an arithmetic number, because the mean of its divisors is an integer number (10777660171).

Almost surely, 2^21555320341 is an apocalyptic number.

It is an amenable number.

21555320341 is a deficient number, since it is larger than the sum of its proper divisors (1).

21555320341 is an equidigital number, since it uses as much as digits as its factorization.

21555320341 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 18000, while the sum is 31.

Adding to 21555320341 its reverse (14302355512), we get a palindrome (35857675853).

The spelling of 21555320341 in words is "twenty-one billion, five hundred fifty-five million, three hundred twenty thousand, three hundred forty-one".