2178447851 has 2 divisors, whose sum is σ = 2178447852. Its totient is φ = 2178447850.

The previous prime is 2178447809. The next prime is 2178447871. The reversal of 2178447851 is 1587448712.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2178447851 is a prime.

It is a Sophie Germain prime.

It is a junction number, because it is equal to n+sod(n) for n = 2178447796 and 2178447805.

It is not a weakly prime, because it can be changed into another prime (2178447871) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1089223925 + 1089223926.

It is an arithmetic number, because the mean of its divisors is an integer number (1089223926).

Almost surely, 2^2178447851 is an apocalyptic number.

2178447851 is a deficient number, since it is larger than the sum of its proper divisors (1).

2178447851 is an equidigital number, since it uses as much as digits as its factorization.

2178447851 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 501760, while the sum is 47.

The square root of 2178447851 is about 46673.8454704559. The cubic root of 2178447851 is about 1296.3304506117.

The spelling of 2178447851 in words is "two billion, one hundred seventy-eight million, four hundred forty-seven thousand, eight hundred fifty-one".