2178938081 has 2 divisors, whose sum is σ = 2178938082. Its totient is φ = 2178938080.

The previous prime is 2178938057. The next prime is 2178938101. The reversal of 2178938081 is 1808398712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1458552481 + 720385600 = 38191^2 + 26840^2 .

It is a cyclic number.

It is not a de Polignac number, because 2178938081 - 2¹⁸ = 2178675937 is a prime.

It is a super-2 number, since 2×2178938081² = 9495542321663925122, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (2178938581) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1089469040 + 1089469041.

It is an arithmetic number, because the mean of its divisors is an integer number (1089469041).

Almost surely, 2^2178938081 is an apocalyptic number.

It is an amenable number.

2178938081 is a deficient number, since it is larger than the sum of its proper divisors (1).

2178938081 is an equidigital number, since it uses as much as digits as its factorization.

2178938081 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 193536, while the sum is 47.

The square root of 2178938081 is about 46679.0968314512. The cubic root of 2178938081 is about 1296.4276838187.

The spelling of 2178938081 in words is "two billion, one hundred seventy-eight million, nine hundred thirty-eight thousand, eighty-one".