20490181 has 2 divisors, whose sum is σ = 20490182. Its totient is φ = 20490180.

The previous prime is 20490161. The next prime is 20490191. The reversal of 20490181 is 18109402.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20205025 + 285156 = 4495^2 + 534^2 .

It is a cyclic number.

It is not a de Polignac number, because 20490181 - 2⁵ = 20490149 is a prime.

It is a super-2 number, since 2×20490181² = 839695034825522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20490121) 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, 10245090 + 10245091.

It is an arithmetic number, because the mean of its divisors is an integer number (10245091).

Almost surely, 2^20490181 is an apocalyptic number.

It is an amenable number.

20490181 is a deficient number, since it is larger than the sum of its proper divisors (1).

20490181 is an equidigital number, since it uses as much as digits as its factorization.

20490181 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 576, while the sum is 25.

The square root of 20490181 is about 4526.6081120415. The cubic root of 20490181 is about 273.6414805857.

Adding to 20490181 its reverse (18109402), we get a palindrome (38599583).

The spelling of 20490181 in words is "twenty million, four hundred ninety thousand, one hundred eighty-one".