820664459 has 4 divisors (see below), whose sum is σ = 820833816. Its totient is φ = 820495104.

The previous prime is 820664447. The next prime is 820664483. The reversal of 820664459 is 954466028.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 820664459 - 2⁸ = 820664203 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (820664419) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 77189 + ... + 87174.

It is an arithmetic number, because the mean of its divisors is an integer number (205208454).

Almost surely, 2^820664459 is an apocalyptic number.

820664459 is a deficient number, since it is larger than the sum of its proper divisors (169357).

820664459 is a wasteful number, since it uses less digits than its factorization.

820664459 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169356.

The product of its (nonzero) digits is 414720, while the sum is 44.

The square root of 820664459 is about 28647.2417345894. The cubic root of 820664459 is about 936.2429099471.

The spelling of 820664459 in words is "eight hundred twenty million, six hundred sixty-four thousand, four hundred fifty-nine".