21012221020073 has 2 divisors, whose sum is σ = 21012221020074. Its totient is φ = 21012221020072.

The previous prime is 21012221020067. The next prime is 21012221020127. The reversal of 21012221020073 is 37002012221012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18958465473424 + 2053755546649 = 4354132^2 + 1433093^2 .

It is a cyclic number.

It is not a de Polignac number, because 21012221020073 - 2¹² = 21012221015977 is a prime.

It is not a weakly prime, because it can be changed into another prime (21012221020033) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506110510036 + 10506110510037.

It is an arithmetic number, because the mean of its divisors is an integer number (10506110510037).

Almost surely, 2^{21012221020073} is an apocalyptic number.

It is an amenable number.

21012221020073 is a deficient number, since it is larger than the sum of its proper divisors (1).

21012221020073 is an equidigital number, since it uses as much as digits as its factorization.

21012221020073 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 672, while the sum is 23.

Adding to 21012221020073 its reverse (37002012221012), we get a palindrome (58014233241085).

The spelling of 21012221020073 in words is "twenty-one trillion, twelve billion, two hundred twenty-one million, twenty thousand, seventy-three".