823201638 has 64 divisors (see below), whose sum is σ = 1984573440. Its totient is φ = 222378912.

The previous prime is 823201609. The next prime is 823201651. The reversal of 823201638 is 836102328.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 823201599 and 823201608.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 707245 + ... + 708407.

It is an arithmetic number, because the mean of its divisors is an integer number (31008960).

Almost surely, 2^823201638 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 823201638, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (992286720).

823201638 is an abundant number, since it is smaller than the sum of its proper divisors (1161371802).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

823201638 is a wasteful number, since it uses less digits than its factorization.

823201638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2081.

The product of its (nonzero) digits is 13824, while the sum is 33.

The square root of 823201638 is about 28691.4906897498. The cubic root of 823201638 is about 937.2067517309.

The spelling of 823201638 in words is "eight hundred twenty-three million, two hundred one thousand, six hundred thirty-eight".