80543821 has 2 divisors, whose sum is σ = 80543822. Its totient is φ = 80543820.

The previous prime is 80543819. The next prime is 80543833. The reversal of 80543821 is 12834508.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 77264100 + 3279721 = 8790^2 + 1811^2 .

It is a cyclic number.

It is not a de Polignac number, because 80543821 - 2¹ = 80543819 is a prime.

Together with 80543819, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (80543521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40271910 + 40271911.

It is an arithmetic number, because the mean of its divisors is an integer number (40271911).

Almost surely, 2^80543821 is an apocalyptic number.

It is an amenable number.

80543821 is a deficient number, since it is larger than the sum of its proper divisors (1).

80543821 is an equidigital number, since it uses as much as digits as its factorization.

80543821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7680, while the sum is 31.

The square root of 80543821 is about 8974.6209390704. The cubic root of 80543821 is about 431.8610896686.

The spelling of 80543821 in words is "eighty million, five hundred forty-three thousand, eight hundred twenty-one".