840182821 has 2 divisors, whose sum is σ = 840182822. Its totient is φ = 840182820.

The previous prime is 840182807. The next prime is 840182899. The reversal of 840182821 is 128281048.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 462852196 + 377330625 = 21514^2 + 19425^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-840182821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (840182521) 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, 420091410 + 420091411.

It is an arithmetic number, because the mean of its divisors is an integer number (420091411).

Almost surely, 2^840182821 is an apocalyptic number.

It is an amenable number.

840182821 is a deficient number, since it is larger than the sum of its proper divisors (1).

840182821 is an equidigital number, since it uses as much as digits as its factorization.

840182821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8192, while the sum is 34.

The square root of 840182821 is about 28985.9072826779. The cubic root of 840182821 is about 943.6072429654.

The spelling of 840182821 in words is "eight hundred forty million, one hundred eighty-two thousand, eight hundred twenty-one".