20798161 has 2 divisors, whose sum is σ = 20798162. Its totient is φ = 20798160.

The previous prime is 20798159. The next prime is 20798171. The reversal of 20798161 is 16189702.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14326225 + 6471936 = 3785^2 + 2544^2 .

It is a cyclic number.

It is not a de Polignac number, because 20798161 - 2¹ = 20798159 is a prime.

Together with 20798159, it forms a pair of twin primes.

It is the 4561-st Hogben number.

It is not a weakly prime, because it can be changed into another prime (20798171) by changing a digit.

It is a nontrivial repunit in base 4560.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10399080 + 10399081.

It is an arithmetic number, because the mean of its divisors is an integer number (10399081).

Almost surely, 2^20798161 is an apocalyptic number.

It is an amenable number.

20798161 is a deficient number, since it is larger than the sum of its proper divisors (1).

20798161 is an equidigital number, since it uses as much as digits as its factorization.

20798161 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6048, while the sum is 34.

The square root of 20798161 is about 4560.5000822278. The cubic root of 20798161 is about 275.0056682027.

The spelling of 20798161 in words is "twenty million, seven hundred ninety-eight thousand, one hundred sixty-one".