27989881 has 2 divisors, whose sum is σ = 27989882. Its totient is φ = 27989880.

The previous prime is 27989821. The next prime is 27989891. The reversal of 27989881 is 18898972.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 27206656 + 783225 = 5216^2 + 885^2 .

It is a cyclic number.

It is not a de Polignac number, because 27989881 - 2⁹ = 27989369 is a prime.

It is a super-2 number, since 2×27989881² = 1566866876788322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (27989821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13994940 + 13994941.

It is an arithmetic number, because the mean of its divisors is an integer number (13994941).

Almost surely, 2^27989881 is an apocalyptic number.

It is an amenable number.

27989881 is a deficient number, since it is larger than the sum of its proper divisors (1).

27989881 is an equidigital number, since it uses as much as digits as its factorization.

27989881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 580608, while the sum is 52.

The square root of 27989881 is about 5290.5463801010. The cubic root of 27989881 is about 303.6223127279.

Subtracting from 27989881 its reverse (18898972), we obtain a palindrome (9090909).

The spelling of 27989881 in words is "twenty-seven million, nine hundred eighty-nine thousand, eight hundred eighty-one".