28628591 has 2 divisors, whose sum is σ = 28628592. Its totient is φ = 28628590.

The previous prime is 28628519. The next prime is 28628603. The reversal of 28628591 is 19582682.

Together with previous prime (28628519) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28628591 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28628791) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14314295 + 14314296.

It is an arithmetic number, because the mean of its divisors is an integer number (14314296).

Almost surely, 2^28628591 is an apocalyptic number.

28628591 is a deficient number, since it is larger than the sum of its proper divisors (1).

28628591 is an equidigital number, since it uses as much as digits as its factorization.

28628591 is an evil number, because the sum of its binary digits is even.

The product of its digits is 69120, while the sum is 41.

The square root of 28628591 is about 5350.5692220548. The cubic root of 28628591 is about 305.9144498624.

The spelling of 28628591 in words is "twenty-eight million, six hundred twenty-eight thousand, five hundred ninety-one".