28978913 has 2 divisors, whose sum is σ = 28978914. Its totient is φ = 28978912.

The previous prime is 28978889. The next prime is 28978927. The reversal of 28978913 is 31987982.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15816529 + 13162384 = 3977^2 + 3628^2 .

It is a cyclic number.

It is not a de Polignac number, because 28978913 - 2⁸ = 28978657 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (28978973) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14489456 + 14489457.

It is an arithmetic number, because the mean of its divisors is an integer number (14489457).

Almost surely, 2^28978913 is an apocalyptic number.

It is an amenable number.

28978913 is a deficient number, since it is larger than the sum of its proper divisors (1).

28978913 is an equidigital number, since it uses as much as digits as its factorization.

28978913 is an evil number, because the sum of its binary digits is even.

The product of its digits is 217728, while the sum is 47.

The square root of 28978913 is about 5383.2065722950. The cubic root of 28978913 is about 307.1571979088.

The spelling of 28978913 in words is "twenty-eight million, nine hundred seventy-eight thousand, nine hundred thirteen".