821587442 has 16 divisors (see below), whose sum is σ = 1363051032. Its totient is φ = 368945280.

The previous prime is 821587427. The next prime is 821587447. The reversal of 821587442 is 244785128.

It can be written as a sum of positive squares in 4 ways, for example, as 690690961 + 130896481 = 26281^2 + 11441^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 821587442.

It is not an unprimeable number, because it can be changed into a prime (821587447) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 426059 + ... + 427982.

Almost surely, 2^821587442 is an apocalyptic number.

821587442 is a deficient number, since it is larger than the sum of its proper divisors (541463590).

821587442 is a wasteful number, since it uses less digits than its factorization.

821587442 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 854093.

The product of its digits is 143360, while the sum is 41.

The square root of 821587442 is about 28663.3466643377. The cubic root of 821587442 is about 936.5937689469.

The spelling of 821587442 in words is "eight hundred twenty-one million, five hundred eighty-seven thousand, four hundred forty-two".