1004393821 has 4 divisors (see below), whose sum is σ = 1004692032. Its totient is φ = 1004095612.

The previous prime is 1004393791. The next prime is 1004393857. The reversal of 1004393821 is 1283934001.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1004393821 - 2⁹ = 1004393309 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1004393861) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 143995 + ... + 150808.

It is an arithmetic number, because the mean of its divisors is an integer number (251173008).

Almost surely, 2^1004393821 is an apocalyptic number.

It is an amenable number.

1004393821 is a deficient number, since it is larger than the sum of its proper divisors (298211).

1004393821 is an equidigital number, since it uses as much as digits as its factorization.

1004393821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 298210.

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 1004393821 is about 31692.1728664981. The cubic root of 1004393821 is about 1001.4624671472.

Subtracting from 1004393821 its sum of digits (31), we obtain a triangular number (1004393790 = T₄₄₈₁₉).

The spelling of 1004393821 in words is "one billion, four million, three hundred ninety-three thousand, eight hundred twenty-one".