28556989 has 2 divisors, whose sum is σ = 28556990. Its totient is φ = 28556988.

The previous prime is 28556977. The next prime is 28556993. The reversal of 28556989 is 98965582.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20548089 + 8008900 = 4533^2 + 2830^2 .

It is a cyclic number.

It is not a de Polignac number, because 28556989 - 2¹¹ = 28554941 is a prime.

It is a super-2 number, since 2×28556989² = 1631003241492242, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28556929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14278494 + 14278495.

It is an arithmetic number, because the mean of its divisors is an integer number (14278495).

Almost surely, 2^28556989 is an apocalyptic number.

It is an amenable number.

28556989 is a deficient number, since it is larger than the sum of its proper divisors (1).

28556989 is an equidigital number, since it uses as much as digits as its factorization.

28556989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1555200, while the sum is 52.

The square root of 28556989 is about 5343.8739693223. The cubic root of 28556989 is about 305.6591995191.

The spelling of 28556989 in words is "twenty-eight million, five hundred fifty-six thousand, nine hundred eighty-nine".