27991904 has 24 divisors (see below), whose sum is σ = 55251000. Its totient is φ = 13959936.

The previous prime is 27991891. The next prime is 27991907. The reversal of 27991904 is 40919972.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27991907) 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 3 ways as a sum of consecutive naturals, for example, 15092 + ... + 16844.

It is an arithmetic number, because the mean of its divisors is an integer number (2302125).

Almost surely, 2^27991904 is an apocalyptic number.

It is an amenable number.

27991904 is a deficient number, since it is larger than the sum of its proper divisors (27259096).

27991904 is a wasteful number, since it uses less digits than its factorization.

27991904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2262 (or 2254 counting only the distinct ones).

The product of its (nonzero) digits is 40824, while the sum is 41.

The square root of 27991904 is about 5290.7375667292. The cubic root of 27991904 is about 303.6296274326.

The spelling of 27991904 in words is "twenty-seven million, nine hundred ninety-one thousand, nine hundred four".