21353450161 has 2 divisors, whose sum is σ = 21353450162. Its totient is φ = 21353450160.

The previous prime is 21353450159. The next prime is 21353450207. The reversal of 21353450161 is 16105435312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19305435136 + 2048015025 = 138944^2 + 45255^2 .

It is a cyclic number.

It is not a de Polignac number, because 21353450161 - 2¹ = 21353450159 is a prime.

Together with 21353450159, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21353450761) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10676725080 + 10676725081.

It is an arithmetic number, because the mean of its divisors is an integer number (10676725081).

Almost surely, 2^21353450161 is an apocalyptic number.

It is an amenable number.

21353450161 is a deficient number, since it is larger than the sum of its proper divisors (1).

21353450161 is an equidigital number, since it uses as much as digits as its factorization.

21353450161 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10800, while the sum is 31.

Adding to 21353450161 its reverse (16105435312), we get a palindrome (37458885473).

The spelling of 21353450161 in words is "twenty-one billion, three hundred fifty-three million, four hundred fifty thousand, one hundred sixty-one".