2181394447 has 2 divisors, whose sum is σ = 2181394448. Its totient is φ = 2181394446.

The previous prime is 2181394441. The next prime is 2181394477. The reversal of 2181394447 is 7444931812.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2181394447 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2181394441) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1090697223 + 1090697224.

It is an arithmetic number, because the mean of its divisors is an integer number (1090697224).

Almost surely, 2^2181394447 is an apocalyptic number.

2181394447 is a deficient number, since it is larger than the sum of its proper divisors (1).

2181394447 is an equidigital number, since it uses as much as digits as its factorization.

2181394447 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 193536, while the sum is 43.

The square root of 2181394447 is about 46705.4006192003. The cubic root of 2181394447 is about 1296.9146649170.

The spelling of 2181394447 in words is "two billion, one hundred eighty-one million, three hundred ninety-four thousand, four hundred forty-seven".