28856981 has 2 divisors, whose sum is σ = 28856982. Its totient is φ = 28856980.

The previous prime is 28856969. The next prime is 28856983. The reversal of 28856981 is 18965882.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18190225 + 10666756 = 4265^2 + 3266^2 .

It is a cyclic number.

It is not a de Polignac number, because 28856981 - 2⁶ = 28856917 is a prime.

It is a super-2 number, since 2×28856981² = 1665450704868722, which contains 22 as substring.

Together with 28856983, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28856983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14428490 + 14428491.

It is an arithmetic number, because the mean of its divisors is an integer number (14428491).

Almost surely, 2^28856981 is an apocalyptic number.

It is an amenable number.

28856981 is a deficient number, since it is larger than the sum of its proper divisors (1).

28856981 is an equidigital number, since it uses as much as digits as its factorization.

28856981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 276480, while the sum is 47.

The square root of 28856981 is about 5371.8694139005. The cubic root of 28856981 is about 306.7257929211.

The spelling of 28856981 in words is "twenty-eight million, eight hundred fifty-six thousand, nine hundred eighty-one".