820420642 has 16 divisors (see below), whose sum is σ = 1271999232. Its totient is φ = 396455760.

The previous prime is 820420639. The next prime is 820420651. The reversal of 820420642 is 246024028.

It is a self number, because there is not a number n which added to its sum of digits gives 820420642.

It is an unprimeable number.

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 in 7 ways as a sum of consecutive naturals, for example, 41113 + ... + 57715.

It is an arithmetic number, because the mean of its divisors is an integer number (79499952).

Almost surely, 2^820420642 is an apocalyptic number.

820420642 is a deficient number, since it is larger than the sum of its proper divisors (451578590).

820420642 is a wasteful number, since it uses less digits than its factorization.

820420642 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17433.

The product of its (nonzero) digits is 6144, while the sum is 28.

The square root of 820420642 is about 28642.9859127850. The cubic root of 820420642 is about 936.1501824240.

The spelling of 820420642 in words is "eight hundred twenty million, four hundred twenty thousand, six hundred forty-two".