21003121169 has 2 divisors, whose sum is σ = 21003121170. Its totient is φ = 21003121168.

The previous prime is 21003121159. The next prime is 21003121213. The reversal of 21003121169 is 96112130012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11572380625 + 9430740544 = 107575^2 + 97112^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21003121169 is a prime.

It is a super-2 number, since 2×21003121169² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21003121159) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10501560584 + 10501560585.

It is an arithmetic number, because the mean of its divisors is an integer number (10501560585).

Almost surely, 2^21003121169 is an apocalyptic number.

It is an amenable number.

21003121169 is a deficient number, since it is larger than the sum of its proper divisors (1).

21003121169 is an equidigital number, since it uses as much as digits as its factorization.

21003121169 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 648, while the sum is 26.

The spelling of 21003121169 in words is "twenty-one billion, three million, one hundred twenty-one thousand, one hundred sixty-nine".