821215842 has 32 divisors (see below), whose sum is σ = 1662094080. Its totient is φ = 270481680.

The previous prime is 821215841. The next prime is 821215859. The reversal of 821215842 is 248512128.

It is not an unprimeable number, because it can be changed into a prime (821215841) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 172717 + ... + 177407.

It is an arithmetic number, because the mean of its divisors is an integer number (51940440).

Almost surely, 2^821215842 is an apocalyptic number.

821215842 is an abundant number, since it is smaller than the sum of its proper divisors (840878238).

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

821215842 is a wasteful number, since it uses less digits than its factorization.

821215842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5038.

The product of its digits is 10240, while the sum is 33.

The square root of 821215842 is about 28656.8637851388. The cubic root of 821215842 is about 936.4525420521.

The spelling of 821215842 in words is "eight hundred twenty-one million, two hundred fifteen thousand, eight hundred forty-two".