28978661 has 2 divisors, whose sum is σ = 28978662. Its totient is φ = 28978660.

The previous prime is 28978657. The next prime is 28978673. The reversal of 28978661 is 16687982.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16240900 + 12737761 = 4030^2 + 3569^2 .

It is a cyclic number.

It is not a de Polignac number, because 28978661 - 2² = 28978657 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28978681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14489330 + 14489331.

It is an arithmetic number, because the mean of its divisors is an integer number (14489331).

Almost surely, 2^28978661 is an apocalyptic number.

It is an amenable number.

28978661 is a deficient number, since it is larger than the sum of its proper divisors (1).

28978661 is an equidigital number, since it uses as much as digits as its factorization.

28978661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 290304, while the sum is 47.

The square root of 28978661 is about 5383.1831661202. The cubic root of 28978661 is about 307.1563075621.

The spelling of 28978661 in words is "twenty-eight million, nine hundred seventy-eight thousand, six hundred sixty-one".