7821279844 has 27 divisors (see below), whose sum is σ = 15924411993. Its totient is φ = 3351446448.

The previous prime is 7821279827. The next prime is 7821279853. The reversal of 7821279844 is 4489721287.

The square root of 7821279844 is 88438.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 4210712100 + 3610567744 = 64890^2 + 60088^2 .

It is a super-2 number, since 2×7821279844² (a number of 21 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (52) coincides with the sum of the digits of its prime factors.

It is a junction number, because it is equal to n+sod(n) for n = 7821279791 and 7821279800.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 1234974 + ... + 1241290.

Almost surely, 2^7821279844 is an apocalyptic number.

7821279844 is the 88438-th square number.

It is an amenable number.

7821279844 is an abundant number, since it is smaller than the sum of its proper divisors (8103132149).

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

7821279844 is an frugal number, since it uses more digits than its factorization.

7821279844 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12652 (or 6326 counting only the distinct ones).

The product of its digits is 1806336, while the sum is 52.

The cubic root of 7821279844 is about 1984.9943504757.

The spelling of 7821279844 in words is "seven billion, eight hundred twenty-one million, two hundred seventy-nine thousand, eight hundred forty-four".