21030321161 has 2 divisors, whose sum is σ = 21030321162. Its totient is φ = 21030321160.

The previous prime is 21030321113. The next prime is 21030321173. The reversal of 21030321161 is 16112303012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12115184761 + 8915136400 = 110069^2 + 94420^2 .

It is a cyclic number.

It is not a de Polignac number, because 21030321161 - 2³⁴ = 3850451977 is a prime.

It is not a weakly prime, because it can be changed into another prime (21030321061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10515160580 + 10515160581.

It is an arithmetic number, because the mean of its divisors is an integer number (10515160581).

Almost surely, 2^21030321161 is an apocalyptic number.

It is an amenable number.

21030321161 is a deficient number, since it is larger than the sum of its proper divisors (1).

21030321161 is an equidigital number, since it uses as much as digits as its factorization.

21030321161 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 216, while the sum is 20.

Adding to 21030321161 its reverse (16112303012), we get a palindrome (37142624173).

The spelling of 21030321161 in words is "twenty-one billion, thirty million, three hundred twenty-one thousand, one hundred sixty-one".