820409638 has 4 divisors (see below), whose sum is σ = 1230614460. Its totient is φ = 410204818.

The previous prime is 820409593. The next prime is 820409651. The reversal of 820409638 is 836904028.

820409638 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a self number, because there is not a number n which added to its sum of digits gives 820409638.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 205102408 + ... + 205102411.

It is an arithmetic number, because the mean of its divisors is an integer number (307653615).

Almost surely, 2^820409638 is an apocalyptic number.

820409638 is a deficient number, since it is larger than the sum of its proper divisors (410204822).

820409638 is a wasteful number, since it uses less digits than its factorization.

820409638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 410204821.

The product of its (nonzero) digits is 82944, while the sum is 40.

The square root of 820409638 is about 28642.7938232289. The cubic root of 820409638 is about 936.1459969927.

The spelling of 820409638 in words is "eight hundred twenty million, four hundred nine thousand, six hundred thirty-eight".