21012213440173 has 2 divisors, whose sum is σ = 21012213440174. Its totient is φ = 21012213440172.

The previous prime is 21012213440143. The next prime is 21012213440249. The reversal of 21012213440173 is 37104431221012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20496146489289 + 516066950884 = 4527267^2 + 718378^2 .

It is a cyclic number.

It is not a de Polignac number, because 21012213440173 - 2³³ = 21003623505581 is a prime.

It is a super-2 number, since 2×21012213440173² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21012213440143) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506106720086 + 10506106720087.

It is an arithmetic number, because the mean of its divisors is an integer number (10506106720087).

Almost surely, 2^{21012213440173} is an apocalyptic number.

It is an amenable number.

21012213440173 is a deficient number, since it is larger than the sum of its proper divisors (1).

21012213440173 is an equidigital number, since it uses as much as digits as its factorization.

21012213440173 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8064, while the sum is 31.

Adding to 21012213440173 its reverse (37104431221012), we get a palindrome (58116644661185).

The spelling of 21012213440173 in words is "twenty-one trillion, twelve billion, two hundred thirteen million, four hundred forty thousand, one hundred seventy-three".