820044002 has 6 divisors (see below), whose sum is σ = 1230126753. Its totient is φ = 410001752.

The previous prime is 820043969. The next prime is 820044019. The reversal of 820044002 is 200440028.

It can be written as a sum of positive squares in 2 ways, for example, as 784056001 + 35988001 = 28001^2 + 5999^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=20249.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 30374 + ... + 50622.

Almost surely, 2^820044002 is an apocalyptic number.

820044002 is a deficient number, since it is larger than the sum of its proper divisors (410082751).

820044002 is an frugal number, since it uses more digits than its factorization.

820044002 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40500 (or 20251 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 20.

The square root of 820044002 is about 28636.4104244928. The cubic root of 820044002 is about 936.0069040631.

Multiplying 820044002 by its product of nonzero digits (512), we get a square (419862529024 = 647968²).

The spelling of 820044002 in words is "eight hundred twenty million, forty-four thousand, two".