21163523153173 has 2 divisors, whose sum is σ = 21163523153174. Its totient is φ = 21163523153172.

The previous prime is 21163523153159. The next prime is 21163523153219. The reversal of 21163523153173 is 37135132536112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15347409550929 + 5816113602244 = 3917577^2 + 2411662^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21163523153173 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21163523153273) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10581761576586 + 10581761576587.

It is an arithmetic number, because the mean of its divisors is an integer number (10581761576587).

Almost surely, 2^{21163523153173} is an apocalyptic number.

It is an amenable number.

21163523153173 is a deficient number, since it is larger than the sum of its proper divisors (1).

21163523153173 is an equidigital number, since it uses as much as digits as its factorization.

21163523153173 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 340200, while the sum is 43.

Adding to 21163523153173 its reverse (37135132536112), we get a palindrome (58298655689285).

The spelling of 21163523153173 in words is "twenty-one trillion, one hundred sixty-three billion, five hundred twenty-three million, one hundred fifty-three thousand, one hundred seventy-three".