20028181 has 2 divisors, whose sum is σ = 20028182. Its totient is φ = 20028180.

The previous prime is 20028179. The next prime is 20028209. The reversal of 20028181 is 18182002.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10048900 + 9979281 = 3170^2 + 3159^2 .

It is a cyclic number.

It is not a de Polignac number, because 20028181 - 2¹ = 20028179 is a prime.

It is a super-2 number, since 2×20028181² = 802256068337522, which contains 22 as substring.

Together with 20028179, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20028121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10014090 + 10014091.

It is an arithmetic number, because the mean of its divisors is an integer number (10014091).

Almost surely, 2^20028181 is an apocalyptic number.

It is an amenable number.

20028181 is a deficient number, since it is larger than the sum of its proper divisors (1).

20028181 is an equidigital number, since it uses as much as digits as its factorization.

20028181 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 256, while the sum is 22.

The square root of 20028181 is about 4475.2855774799. The cubic root of 20028181 is about 271.5691934970.

The spelling of 20028181 in words is "twenty million, twenty-eight thousand, one hundred eighty-one".