27981388 has 12 divisors (see below), whose sum is σ = 51847992. Its totient is φ = 13167680.

The previous prime is 27981383. The next prime is 27981391. The reversal of 27981388 is 88318972.

It is not an unprimeable number, because it can be changed into a prime (27981383) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 205678 + ... + 205813.

It is an arithmetic number, because the mean of its divisors is an integer number (4320666).

Almost surely, 2^27981388 is an apocalyptic number.

It is an amenable number.

27981388 is a deficient number, since it is larger than the sum of its proper divisors (23866604).

27981388 is a wasteful number, since it uses less digits than its factorization.

27981388 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 411512 (or 411510 counting only the distinct ones).

The product of its digits is 193536, while the sum is 46.

The square root of 27981388 is about 5289.7436610860. The cubic root of 27981388 is about 303.5916001386.

It can be divided in two parts, 2798 and 1388, that added together give a triangular number (4186 = T₉₁).

The spelling of 27981388 in words is "twenty-seven million, nine hundred eighty-one thousand, three hundred eighty-eight".