21003303121 has 2 divisors, whose sum is σ = 21003303122. Its totient is φ = 21003303120.

The previous prime is 21003303091. The next prime is 21003303137. The reversal of 21003303121 is 12130330012.

It is an a-pointer prime, because the next prime (21003303137) can be obtained adding 21003303121 to its sum of digits (16).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17678627521 + 3324675600 = 132961^2 + 57660^2 .

It is a cyclic number.

It is not a de Polignac number, because 21003303121 - 2⁹ = 21003302609 is a prime.

It is a super-2 number, since 2×21003303121² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21003303095 and 21003303104.

It is not a weakly prime, because it can be changed into another prime (21003303161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10501651560 + 10501651561.

It is an arithmetic number, because the mean of its divisors is an integer number (10501651561).

Almost surely, 2^21003303121 is an apocalyptic number.

It is an amenable number.

21003303121 is a deficient number, since it is larger than the sum of its proper divisors (1).

21003303121 is an equidigital number, since it uses as much as digits as its factorization.

21003303121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 108, while the sum is 16.

Adding to 21003303121 its reverse (12130330012), we get a palindrome (33133633133).

The spelling of 21003303121 in words is "twenty-one billion, three million, three hundred three thousand, one hundred twenty-one".