7921805 has 8 divisors (see below), whose sum is σ = 9527544. Its totient is φ = 6323200.

The previous prime is 7921787. The next prime is 7921817. The reversal of 7921805 is 5081297.

7921805 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 2036329 + 5885476 = 1427^2 + 2426^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 7921805 - 2⁸ = 7921549 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1085 + ... + 4125.

It is an arithmetic number, because the mean of its divisors is an integer number (1190943).

Almost surely, 2^7921805 is an apocalyptic number.

It is an amenable number.

7921805 is a deficient number, since it is larger than the sum of its proper divisors (1605739).

7921805 is a wasteful number, since it uses less digits than its factorization.

7921805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3567.

The product of its (nonzero) digits is 5040, while the sum is 32.

The square root of 7921805 is about 2814.5701270354. The cubic root of 7921805 is about 199.3462403199.

The spelling of 7921805 in words is "seven million, nine hundred twenty-one thousand, eight hundred five".