28994991 has 4 divisors (see below), whose sum is σ = 38659992. Its totient is φ = 19329992.

The previous prime is 28994963. The next prime is 28994993. The reversal of 28994991 is 19949982.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 28994991 - 2⁷ = 28994863 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28994993) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4832496 + ... + 4832501.

It is an arithmetic number, because the mean of its divisors is an integer number (9664998).

Almost surely, 2^28994991 is an apocalyptic number.

28994991 is a deficient number, since it is larger than the sum of its proper divisors (9665001).

28994991 is an equidigital number, since it uses as much as digits as its factorization.

28994991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9665000.

The product of its digits is 419904, while the sum is 51.

The square root of 28994991 is about 5384.6997130759. The cubic root of 28994991 is about 307.2139927742.

The spelling of 28994991 in words is "twenty-eight million, nine hundred ninety-four thousand, nine hundred ninety-one".