21010221073 has 2 divisors, whose sum is σ = 21010221074. Its totient is φ = 21010221072.

The previous prime is 21010221053. The next prime is 21010221121. The reversal of 21010221073 is 37012201012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20757029329 + 253191744 = 144073^2 + 15912^2 .

It is a cyclic number.

It is not a de Polignac number, because 21010221073 - 2¹⁷ = 21010090001 is a prime.

It is a super-3 number, since 3×21010221073³ (a number of 32 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21010221073.

It is not a weakly prime, because it can be changed into another prime (21010221053) 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, 10505110536 + 10505110537.

It is an arithmetic number, because the mean of its divisors is an integer number (10505110537).

Almost surely, 2^21010221073 is an apocalyptic number.

It is an amenable number.

21010221073 is a deficient number, since it is larger than the sum of its proper divisors (1).

21010221073 is an equidigital number, since it uses as much as digits as its factorization.

21010221073 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 168, while the sum is 19.

Adding to 21010221073 its reverse (37012201012), we get a palindrome (58022422085).

The spelling of 21010221073 in words is "twenty-one billion, ten million, two hundred twenty-one thousand, seventy-three".