821640472 has 8 divisors (see below), whose sum is σ = 1540575900. Its totient is φ = 410820232.

The previous prime is 821640439. The next prime is 821640487. The reversal of 821640472 is 274046128.

It is a happy number.

821640472 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (8).

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, 51352522 + ... + 51352537.

Almost surely, 2^821640472 is an apocalyptic number.

It is an amenable number.

821640472 is a deficient number, since it is larger than the sum of its proper divisors (718935428).

821640472 is a wasteful number, since it uses less digits than its factorization.

821640472 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102705065 (or 102705061 counting only the distinct ones).

The product of its (nonzero) digits is 21504, while the sum is 34.

The square root of 821640472 is about 28664.2716984053. The cubic root of 821640472 is about 936.6139195709.

The spelling of 821640472 in words is "eight hundred twenty-one million, six hundred forty thousand, four hundred seventy-two".