28840681 has 2 divisors, whose sum is σ = 28840682. Its totient is φ = 28840680.

The previous prime is 28840667. The next prime is 28840699. The reversal of 28840681 is 18604882.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15335056 + 13505625 = 3916^2 + 3675^2 .

It is a cyclic number.

It is not a de Polignac number, because 28840681 - 2¹⁵ = 28807913 is a prime.

It is a super-2 number, since 2×28840681² = 1663569761087522, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28840681.

It is not a weakly prime, because it can be changed into another prime (28840601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14420340 + 14420341.

It is an arithmetic number, because the mean of its divisors is an integer number (14420341).

Almost surely, 2^28840681 is an apocalyptic number.

It is an amenable number.

28840681 is a deficient number, since it is larger than the sum of its proper divisors (1).

28840681 is an equidigital number, since it uses as much as digits as its factorization.

28840681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24576, while the sum is 37.

The square root of 28840681 is about 5370.3520368780. The cubic root of 28840681 is about 306.6680302134.

The spelling of 28840681 in words is "twenty-eight million, eight hundred forty thousand, six hundred eighty-one".