8464439821 has 2 divisors, whose sum is σ = 8464439822. Its totient is φ = 8464439820.

The previous prime is 8464439803. The next prime is 8464439831. The reversal of 8464439821 is 1289344648.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7374515625 + 1089924196 = 85875^2 + 33014^2 .

It is a cyclic number.

It is not a de Polignac number, because 8464439821 - 2⁷ = 8464439693 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8464439801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4232219910 + 4232219911.

It is an arithmetic number, because the mean of its divisors is an integer number (4232219911).

Almost surely, 2^8464439821 is an apocalyptic number.

It is an amenable number.

8464439821 is a deficient number, since it is larger than the sum of its proper divisors (1).

8464439821 is an equidigital number, since it uses as much as digits as its factorization.

8464439821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1327104, while the sum is 49.

The square root of 8464439821 is about 92002.3903004699. The cubic root of 8464439821 is about 2037.9776046042.

The spelling of 8464439821 in words is "eight billion, four hundred sixty-four million, four hundred thirty-nine thousand, eight hundred twenty-one".