21210203320073 has 2 divisors, whose sum is σ = 21210203320074. Its totient is φ = 21210203320072.

The previous prime is 21210203320067. The next prime is 21210203320129. The reversal of 21210203320073 is 37002330201212.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21207609149584 + 2594170489 = 4605172^2 + 50933^2 .

It is a cyclic number.

It is not a de Polignac number, because 21210203320073 - 2¹⁴ = 21210203303689 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21210203322073) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10605101660036 + 10605101660037.

It is an arithmetic number, because the mean of its divisors is an integer number (10605101660037).

Almost surely, 2^{21210203320073} is an apocalyptic number.

It is an amenable number.

21210203320073 is a deficient number, since it is larger than the sum of its proper divisors (1).

21210203320073 is an equidigital number, since it uses as much as digits as its factorization.

21210203320073 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3024, while the sum is 26.

Adding to 21210203320073 its reverse (37002330201212), we get a palindrome (58212533521285).

The spelling of 21210203320073 in words is "twenty-one trillion, two hundred ten billion, two hundred three million, three hundred twenty thousand, seventy-three".