7221645 has 12 divisors (see below), whose sum is σ = 12517596. Its totient is φ = 3851520.

The previous prime is 7221631. The next prime is 7221649. The reversal of 7221645 is 5461227.

7221645 is digitally balanced in base 4, 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 2 ways, for example, as 1432809 + 5788836 = 1197^2 + 2406^2 .

It is not a de Polignac number, because 7221645 - 2⁴ = 7221629 is a prime.

It is a super-3 number, since 3×7221645³ (a number of 22 digits) contains 333 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7221649) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 80196 + ... + 80285.

It is an arithmetic number, because the mean of its divisors is an integer number (1043133).

Almost surely, 2^7221645 is an apocalyptic number.

It is an amenable number.

7221645 is a deficient number, since it is larger than the sum of its proper divisors (5295951).

7221645 is a wasteful number, since it uses less digits than its factorization.

7221645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 160492 (or 160489 counting only the distinct ones).

The product of its digits is 3360, while the sum is 27.

The square root of 7221645 is about 2687.3118538793. The cubic root of 7221645 is about 193.2911835052.

The spelling of 7221645 in words is "seven million, two hundred twenty-one thousand, six hundred forty-five".