7821209004 has 96 divisors (see below), whose sum is σ = 21140560896. Its totient is φ = 2204375040.

The previous prime is 7821209003. The next prime is 7821209047. The reversal of 7821209004 is 4009021287.

It is a happy number.

It is a super-2 number, since 2×7821209004² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (7821209003) 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 31 ways as a sum of consecutive naturals, for example, 2429604 + ... + 2432820.

It is an arithmetic number, because the mean of its divisors is an integer number (220214176).

Almost surely, 2^7821209004 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 7821209004, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10570280448).

7821209004 is an abundant number, since it is smaller than the sum of its proper divisors (13319351892).

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

7821209004 is a wasteful number, since it uses less digits than its factorization.

7821209004 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3615 (or 3613 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 33.

The square root of 7821209004 is about 88437.5994925235. The cubic root of 7821209004 is about 1984.9883575340.

The spelling of 7821209004 in words is "seven billion, eight hundred twenty-one million, two hundred nine thousand, four".