28090081 has 2 divisors, whose sum is σ = 28090082. Its totient is φ = 28090080.

The previous prime is 28090039. The next prime is 28090087. The reversal of 28090081 is 18009082.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 28090000 + 81 = 5300^2 + 9^2 .

It is a cyclic number.

It is not a de Polignac number, because 28090081 - 2⁹ = 28089569 is a prime.

It is a super-2 number, since 2×28090081² = 1578105301173122, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (28090087) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14045040 + 14045041.

It is an arithmetic number, because the mean of its divisors is an integer number (14045041).

Almost surely, 2^28090081 is an apocalyptic number.

It is an amenable number.

28090081 is a deficient number, since it is larger than the sum of its proper divisors (1).

28090081 is an equidigital number, since it uses as much as digits as its factorization.

28090081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1152, while the sum is 28.

The square root of 28090081 is about 5300.0076415039. The cubic root of 28090081 is about 303.9841902270.

It can be divided in two parts, 280900 and 81, that multiplied together give a square (22752900 = 4770²).

The spelling of 28090081 in words is "twenty-eight million, ninety thousand, eighty-one".