20655181 has 2 divisors, whose sum is σ = 20655182. Its totient is φ = 20655180.

The previous prime is 20655169. The next prime is 20655199. The reversal of 20655181 is 18155602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12187081 + 8468100 = 3491^2 + 2910^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20655181 is a prime.

It is a super-2 number, since 2×20655181² = 853273004285522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20655101) 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, 10327590 + 10327591.

It is an arithmetic number, because the mean of its divisors is an integer number (10327591).

Almost surely, 2^20655181 is an apocalyptic number.

It is an amenable number.

20655181 is a deficient number, since it is larger than the sum of its proper divisors (1).

20655181 is an equidigital number, since it uses as much as digits as its factorization.

20655181 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2400, while the sum is 28.

The square root of 20655181 is about 4544.7971351866. The cubic root of 20655181 is about 274.3740296560.

The spelling of 20655181 in words is "twenty million, six hundred fifty-five thousand, one hundred eighty-one".