7721345 has 8 divisors (see below), whose sum is σ = 9516264. Its totient is φ = 6009984.

The previous prime is 7721339. The next prime is 7721347. The reversal of 7721345 is 5431277.

It can be written as a sum of positive squares in 4 ways, for example, as 4648336 + 3073009 = 2156^2 + 1753^2 .

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

It is not a de Polignac number, because 7721345 - 2¹⁸ = 7459201 is a prime.

It is a d-powerful number, because it can be written as 7³ + 7⁸ + 2¹¹ + 1 + 3 + 4⁵ + 5⁹ .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7721347) by changing a digit.

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, 20684 + ... + 21053.

It is an arithmetic number, because the mean of its divisors is an integer number (1189533).

Almost surely, 2^7721345 is an apocalyptic number.

It is an amenable number.

7721345 is a deficient number, since it is larger than the sum of its proper divisors (1794919).

7721345 is a wasteful number, since it uses less digits than its factorization.

7721345 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41779.

The product of its digits is 5880, while the sum is 29.

The square root of 7721345 is about 2778.7308253949. The cubic root of 7721345 is about 197.6503795144.

The spelling of 7721345 in words is "seven million, seven hundred twenty-one thousand, three hundred forty-five".