27950831981 has 2 divisors, whose sum is σ = 27950831982. Its totient is φ = 27950831980.

The previous prime is 27950831947. The next prime is 27950832001. The reversal of 27950831981 is 18913805972.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 27248104900 + 702727081 = 165070^2 + 26509^2 .

It is a cyclic number.

It is not a de Polignac number, because 27950831981 - 2¹⁴ = 27950815597 is a prime.

It is a super-2 number, since 2×27950831981² (a number of 22 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (27950831941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13975415990 + 13975415991.

It is an arithmetic number, because the mean of its divisors is an integer number (13975415991).

Almost surely, 2^27950831981 is an apocalyptic number.

It is an amenable number.

27950831981 is a deficient number, since it is larger than the sum of its proper divisors (1).

27950831981 is an equidigital number, since it uses as much as digits as its factorization.

27950831981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1088640, while the sum is 53.

The spelling of 27950831981 in words is "twenty-seven billion, nine hundred fifty million, eight hundred thirty-one thousand, nine hundred eighty-one".