28780181 has 2 divisors, whose sum is σ = 28780182. Its totient is φ = 28780180.

The previous prime is 28780159. The next prime is 28780207. The reversal of 28780181 is 18108782.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20566225 + 8213956 = 4535^2 + 2866^2 .

It is a cyclic number.

It is not a de Polignac number, because 28780181 - 2¹⁴ = 28763797 is a prime.

It is a super-2 number, since 2×28780181² = 1656597636785522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28780681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14390090 + 14390091.

It is an arithmetic number, because the mean of its divisors is an integer number (14390091).

Almost surely, 2^28780181 is an apocalyptic number.

It is an amenable number.

28780181 is a deficient number, since it is larger than the sum of its proper divisors (1).

28780181 is an equidigital number, since it uses as much as digits as its factorization.

28780181 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7168, while the sum is 35.

The square root of 28780181 is about 5364.7163019120. The cubic root of 28780181 is about 306.4534443844.

The spelling of 28780181 in words is "twenty-eight million, seven hundred eighty thousand, one hundred eighty-one".