821724812 has 24 divisors (see below), whose sum is σ = 1493896320. Its totient is φ = 395066880.

The previous prime is 821724809. The next prime is 821724821. The reversal of 821724812 is 218427128.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1637 + ... + 40572.

It is an arithmetic number, because the mean of its divisors is an integer number (62245680).

Almost surely, 2^821724812 is an apocalyptic number.

It is an amenable number.

821724812 is a deficient number, since it is larger than the sum of its proper divisors (672171508).

821724812 is a wasteful number, since it uses less digits than its factorization.

821724812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42401 (or 42399 counting only the distinct ones).

The product of its digits is 14336, while the sum is 35.

The square root of 821724812 is about 28665.7428300751. The cubic root of 821724812 is about 936.6459657509.

The spelling of 821724812 in words is "eight hundred twenty-one million, seven hundred twenty-four thousand, eight hundred twelve".