28948991 has 4 divisors (see below), whose sum is σ = 29023800. Its totient is φ = 28874184.

The previous prime is 28948987. The next prime is 28949003. The reversal of 28948991 is 19984982.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19984982 = 2 ⋅9992491.

It is a cyclic number.

It is not a de Polignac number, because 28948991 - 2² = 28948987 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28948921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 36821 + ... + 37598.

It is an arithmetic number, because the mean of its divisors is an integer number (7255950).

Almost surely, 2^28948991 is an apocalyptic number.

28948991 is a deficient number, since it is larger than the sum of its proper divisors (74809).

28948991 is an equidigital number, since it uses as much as digits as its factorization.

28948991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 74808.

The product of its digits is 373248, while the sum is 50.

The square root of 28948991 is about 5380.4266559447. The cubic root of 28948991 is about 307.0514437376.

The spelling of 28948991 in words is "twenty-eight million, nine hundred forty-eight thousand, nine hundred ninety-one".