27311981 has 4 divisors (see below), whose sum is σ = 27323712. Its totient is φ = 27300252.

The previous prime is 27311969. The next prime is 27311983. The reversal of 27311981 is 18911372.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 27311981 - 2⁶ = 27311917 is a prime.

It is a super-2 number, since 2×27311981² = 1491888612288722, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (27311983) 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, 1061 + ... + 7466.

It is an arithmetic number, because the mean of its divisors is an integer number (6830928).

Almost surely, 2^27311981 is an apocalyptic number.

It is an amenable number.

27311981 is a deficient number, since it is larger than the sum of its proper divisors (11731).

27311981 is an equidigital number, since it uses as much as digits as its factorization.

27311981 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11730.

The product of its digits is 3024, while the sum is 32.

The square root of 27311981 is about 5226.0865855820. The cubic root of 27311981 is about 301.1510630495.

The spelling of 27311981 in words is "twenty-seven million, three hundred eleven thousand, nine hundred eighty-one".