27904607981 has 2 divisors, whose sum is σ = 27904607982. Its totient is φ = 27904607980.

The previous prime is 27904607903. The next prime is 27904608007. The reversal of 27904607981 is 18970640972.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23929305481 + 3975302500 = 154691^2 + 63050^2 .

It is a cyclic number.

It is not a de Polignac number, because 27904607981 - 2²² = 27900413677 is a prime.

It is a super-2 number, since 2×27904607981² (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 (27904607581) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 13952303990 + 13952303991.

It is an arithmetic number, because the mean of its divisors is an integer number (13952303991).

Almost surely, 2^27904607981 is an apocalyptic number.

It is an amenable number.

27904607981 is a deficient number, since it is larger than the sum of its proper divisors (1).

27904607981 is an equidigital number, since it uses as much as digits as its factorization.

27904607981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1524096, while the sum is 53.

The spelling of 27904607981 in words is "twenty-seven billion, nine hundred four million, six hundred seven thousand, nine hundred eighty-one".