27731843681 has 2 divisors, whose sum is σ = 27731843682. Its totient is φ = 27731843680.

The previous prime is 27731843677. The next prime is 27731843707. The reversal of 27731843681 is 18634813772.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 25502493025 + 2229350656 = 159695^2 + 47216^2 .

It is a cyclic number.

It is not a de Polignac number, because 27731843681 - 2² = 27731843677 is a prime.

It is a super-2 number, since 2×27731843681² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (27731843621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13865921840 + 13865921841.

It is an arithmetic number, because the mean of its divisors is an integer number (13865921841).

Almost surely, 2^27731843681 is an apocalyptic number.

It is an amenable number.

27731843681 is a deficient number, since it is larger than the sum of its proper divisors (1).

27731843681 is an equidigital number, since it uses as much as digits as its factorization.

27731843681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1354752, while the sum is 50.

The spelling of 27731843681 in words is "twenty-seven billion, seven hundred thirty-one million, eight hundred forty-three thousand, six hundred eighty-one".