27991880 has 32 divisors (see below), whose sum is σ = 71979840. Its totient is φ = 9597120.

The previous prime is 27991867. The next prime is 27991891. The reversal of 27991880 is 8819972.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 49706 + ... + 50265.

It is an arithmetic number, because the mean of its divisors is an integer number (2249370).

Almost surely, 2^27991880 is an apocalyptic number.

27991880 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

27991880 is an abundant number, since it is smaller than the sum of its proper divisors (43987960).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

27991880 is a wasteful number, since it uses less digits than its factorization.

27991880 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 99989 (or 99985 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 44.

The square root of 27991880 is about 5290.7352986140. The cubic root of 27991880 is about 303.6295406562.

The spelling of 27991880 in words is "twenty-seven million, nine hundred ninety-one thousand, eight hundred eighty".