821645436 has 24 divisors (see below), whose sum is σ = 1924307280. Its totient is φ = 272862592.

The previous prime is 821645431. The next prime is 821645449. The reversal of 821645436 is 634546128.

821645436 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 821645394 and 821645403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821645431) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 124041 + ... + 130496.

It is an arithmetic number, because the mean of its divisors is an integer number (80179470).

Almost surely, 2^821645436 is an apocalyptic number.

It is an amenable number.

821645436 is an abundant number, since it is smaller than the sum of its proper divisors (1102661844).

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

821645436 is a wasteful number, since it uses less digits than its factorization.

821645436 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 254813 (or 254811 counting only the distinct ones).

The product of its digits is 138240, while the sum is 39.

The square root of 821645436 is about 28664.3582869040. The cubic root of 821645436 is about 936.6158057739.

The spelling of 821645436 in words is "eight hundred twenty-one million, six hundred forty-five thousand, four hundred thirty-six".