27143431981 has 2 divisors, whose sum is σ = 27143431982. Its totient is φ = 27143431980.

The previous prime is 27143431979. The next prime is 27143431993. The reversal of 27143431981 is 18913434172.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 25037998756 + 2105433225 = 158234^2 + 45885^2 .

It is a cyclic number.

It is not a de Polignac number, because 27143431981 - 2¹ = 27143431979 is a prime.

It is a super-2 number, since 2×27143431981² (a number of 22 digits) contains 22 as substring.

Together with 27143431979, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (27143431181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13571715990 + 13571715991.

It is an arithmetic number, because the mean of its divisors is an integer number (13571715991).

Almost surely, 2^27143431981 is an apocalyptic number.

It is an amenable number.

27143431981 is a deficient number, since it is larger than the sum of its proper divisors (1).

27143431981 is an equidigital number, since it uses as much as digits as its factorization.

27143431981 is an evil number, because the sum of its binary digits is even.

The product of its digits is 145152, while the sum is 43.

The spelling of 27143431981 in words is "twenty-seven billion, one hundred forty-three million, four hundred thirty-one thousand, nine hundred eighty-one".