28916991 has 12 divisors (see below), whose sum is σ = 41853240. Its totient is φ = 19239120.

The previous prime is 28916981. The next prime is 28917029. The reversal of 28916991 is 19961982.

It is not a de Polignac number, because 28916991 - 2⁷ = 28916863 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28916971) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1900 + ... + 7838.

It is an arithmetic number, because the mean of its divisors is an integer number (3487770).

Almost surely, 2^28916991 is an apocalyptic number.

28916991 is a deficient number, since it is larger than the sum of its proper divisors (12936249).

28916991 is a wasteful number, since it uses less digits than its factorization.

28916991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6486 (or 6483 counting only the distinct ones).

The product of its digits is 69984, while the sum is 45.

The square root of 28916991 is about 5377.4520918368. The cubic root of 28916991 is about 306.9382645618.

The spelling of 28916991 in words is "twenty-eight million, nine hundred sixteen thousand, nine hundred ninety-one".