28547991 has 16 divisors (see below), whose sum is σ = 44133120. Its totient is φ = 18204120.

The previous prime is 28547989. The next prime is 28547999. The reversal of 28547991 is 19974582.

It is not a de Polignac number, because 28547991 - 2¹ = 28547989 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28547999) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22365 + ... + 23606.

It is an arithmetic number, because the mean of its divisors is an integer number (2758320).

Almost surely, 2^28547991 is an apocalyptic number.

28547991 is a deficient number, since it is larger than the sum of its proper divisors (15585129).

28547991 is a wasteful number, since it uses less digits than its factorization.

28547991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 46003 (or 45997 counting only the distinct ones).

The product of its digits is 181440, while the sum is 45.

The square root of 28547991 is about 5343.0320043960. The cubic root of 28547991 is about 305.6270928382.

The spelling of 28547991 in words is "twenty-eight million, five hundred forty-seven thousand, nine hundred ninety-one".