28557493 has 2 divisors, whose sum is σ = 28557494. Its totient is φ = 28557492.

The previous prime is 28557491. The next prime is 28557499. The reversal of 28557493 is 39475582.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 22496049 + 6061444 = 4743^2 + 2462^2 .

It is a cyclic number.

It is not a de Polignac number, because 28557493 - 2¹ = 28557491 is a prime.

Together with 28557491, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28557491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14278746 + 14278747.

It is an arithmetic number, because the mean of its divisors is an integer number (14278747).

Almost surely, 2^28557493 is an apocalyptic number.

It is an amenable number.

28557493 is a deficient number, since it is larger than the sum of its proper divisors (1).

28557493 is an equidigital number, since it uses as much as digits as its factorization.

28557493 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 302400, while the sum is 43.

The square root of 28557493 is about 5343.9211259149. The cubic root of 28557493 is about 305.6609976934.

The spelling of 28557493 in words is "twenty-eight million, five hundred fifty-seven thousand, four hundred ninety-three".