21344442173 has 2 divisors, whose sum is σ = 21344442174. Its totient is φ = 21344442172.

The previous prime is 21344442137. The next prime is 21344442193. The reversal of 21344442173 is 37124444312.

Together with previous prime (21344442137) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20129083129 + 1215359044 = 141877^2 + 34862^2 .

It is a cyclic number.

It is not a de Polignac number, because 21344442173 - 2⁸ = 21344441917 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21344442193) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10672221086 + 10672221087.

It is an arithmetic number, because the mean of its divisors is an integer number (10672221087).

Almost surely, 2^21344442173 is an apocalyptic number.

It is an amenable number.

21344442173 is a deficient number, since it is larger than the sum of its proper divisors (1).

21344442173 is an equidigital number, since it uses as much as digits as its factorization.

21344442173 is an evil number, because the sum of its binary digits is even.

The product of its digits is 64512, while the sum is 35.

Adding to 21344442173 its reverse (37124444312), we get a palindrome (58468886485).

The spelling of 21344442173 in words is "twenty-one billion, three hundred forty-four million, four hundred forty-two thousand, one hundred seventy-three".