28981591 has 2 divisors, whose sum is σ = 28981592. Its totient is φ = 28981590.

The previous prime is 28981573. The next prime is 28981597. The reversal of 28981591 is 19518982.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28981591 is a prime.

It is equal to p_1798585 and since 28981591 and 1798585 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28981597) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14490795 + 14490796.

It is an arithmetic number, because the mean of its divisors is an integer number (14490796).

Almost surely, 2^28981591 is an apocalyptic number.

28981591 is a deficient number, since it is larger than the sum of its proper divisors (1).

28981591 is an equidigital number, since it uses as much as digits as its factorization.

28981591 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 51840, while the sum is 43.

The square root of 28981591 is about 5383.4553030558. The cubic root of 28981591 is about 307.1666592901.

It can be divided in two parts, 2898 and 1591, that added together give a square (4489 = 67²).

The spelling of 28981591 in words is "twenty-eight million, nine hundred eighty-one thousand, five hundred ninety-one".