21101303173 has 2 divisors, whose sum is σ = 21101303174. Its totient is φ = 21101303172.

The previous prime is 21101303059. The next prime is 21101303219. The reversal of 21101303173 is 37130310112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17725460769 + 3375842404 = 133137^2 + 58102^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21101303173 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21101313173) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10550651586 + 10550651587.

It is an arithmetic number, because the mean of its divisors is an integer number (10550651587).

Almost surely, 2^21101303173 is an apocalyptic number.

It is an amenable number.

21101303173 is a deficient number, since it is larger than the sum of its proper divisors (1).

21101303173 is an equidigital number, since it uses as much as digits as its factorization.

21101303173 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 378, while the sum is 22.

Adding to 21101303173 its reverse (37130310112), we get a palindrome (58231613285).

The spelling of 21101303173 in words is "twenty-one billion, one hundred one million, three hundred three thousand, one hundred seventy-three".