21121320001 has 2 divisors, whose sum is σ = 21121320002. Its totient is φ = 21121320000.

The previous prime is 21121319987. The next prime is 21121320071. The reversal of 21121320001 is 10002312112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18393869376 + 2727450625 = 135624^2 + 52225^2 .

It is a cyclic number.

It is not a de Polignac number, because 21121320001 - 2⁵ = 21121319969 is a prime.

It is a super-3 number, since 3×21121320001³ (a number of 32 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not a weakly prime, because it can be changed into another prime (21121320071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560660000 + 10560660001.

It is an arithmetic number, because the mean of its divisors is an integer number (10560660001).

Almost surely, 2^21121320001 is an apocalyptic number.

It is an amenable number.

21121320001 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121320001 is an equidigital number, since it uses as much as digits as its factorization.

21121320001 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24, while the sum is 13.

Adding to 21121320001 its reverse (10002312112), we get a palindrome (31123632113).

The spelling of 21121320001 in words is "twenty-one billion, one hundred twenty-one million, three hundred twenty thousand, one".