28756391 has 2 divisors, whose sum is σ = 28756392. Its totient is φ = 28756390.

The previous prime is 28756327. The next prime is 28756447. The reversal of 28756391 is 19365782.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 28756391 - 2⁶ = 28756327 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 (28758391) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14378195 + 14378196.

It is an arithmetic number, because the mean of its divisors is an integer number (14378196).

Almost surely, 2^28756391 is an apocalyptic number.

28756391 is a deficient number, since it is larger than the sum of its proper divisors (1).

28756391 is an equidigital number, since it uses as much as digits as its factorization.

28756391 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 90720, while the sum is 41.

The square root of 28756391 is about 5362.4985780884. The cubic root of 28756391 is about 306.3689818953.

The spelling of 28756391 in words is "twenty-eight million, seven hundred fifty-six thousand, three hundred ninety-one".