27988821 has 20 divisors (see below), whose sum is σ = 47784352. Its totient is φ = 15993288.

The previous prime is 27988811. The next prime is 27988837. The reversal of 27988821 is 12888972.

It is a happy number.

It is not a de Polignac number, because 27988821 - 2⁵ = 27988789 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27988811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 24115 + ... + 25248.

Almost surely, 2^27988821 is an apocalyptic number.

27988821 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

27988821 is a deficient number, since it is larger than the sum of its proper divisors (19795531).

27988821 is an equidigital number, since it uses as much as digits as its factorization.

27988821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49382 (or 49373 counting only the distinct ones).

The product of its digits is 129024, while the sum is 45.

The square root of 27988821 is about 5290.4462004636. The cubic root of 27988821 is about 303.6184798700.

The spelling of 27988821 in words is "twenty-seven million, nine hundred eighty-eight thousand, eight hundred twenty-one".