21003300061 has 2 divisors, whose sum is σ = 21003300062. Its totient is φ = 21003300060.

The previous prime is 21003300049. The next prime is 21003300173. The reversal of 21003300061 is 16000330012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12283288900 + 8720011161 = 110830^2 + 93381^2 .

It is a cyclic number.

It is not a de Polignac number, because 21003300061 - 2²³ = 20994911453 is a prime.

It is a super-2 number, since 2×21003300061² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21003300001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10501650030 + 10501650031.

It is an arithmetic number, because the mean of its divisors is an integer number (10501650031).

Almost surely, 2^21003300061 is an apocalyptic number.

It is an amenable number.

21003300061 is a deficient number, since it is larger than the sum of its proper divisors (1).

21003300061 is an equidigital number, since it uses as much as digits as its factorization.

21003300061 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 21003300061 its reverse (16000330012), we get a palindrome (37003630073).

The spelling of 21003300061 in words is "twenty-one billion, three million, three hundred thousand, sixty-one".