20655161 has 2 divisors, whose sum is σ = 20655162. Its totient is φ = 20655160.

The previous prime is 20655143. The next prime is 20655169. The reversal of 20655161 is 16155602.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20647936 + 7225 = 4544^2 + 85^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20655161 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20655161.

It is not a weakly prime, because it can be changed into another prime (20655169) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10327580 + 10327581.

It is an arithmetic number, because the mean of its divisors is an integer number (10327581).

Almost surely, 2^20655161 is an apocalyptic number.

It is an amenable number.

20655161 is a deficient number, since it is larger than the sum of its proper divisors (1).

20655161 is an equidigital number, since it uses as much as digits as its factorization.

20655161 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1800, while the sum is 26.

The square root of 20655161 is about 4544.7949348678. The cubic root of 20655161 is about 274.3739410990.

The spelling of 20655161 in words is "twenty million, six hundred fifty-five thousand, one hundred sixty-one".