7221520 has 40 divisors (see below), whose sum is σ = 17677440. Its totient is φ = 2736000.

The previous prime is 7221509. The next prime is 7221523. The reversal of 7221520 is 251227.

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×7221520² = 104300702220800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7221523) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 856 + ... + 3895.

It is an arithmetic number, because the mean of its divisors is an integer number (441936).

Almost surely, 2^7221520 is an apocalyptic number.

It is an amenable number.

7221520 is an abundant number, since it is smaller than the sum of its proper divisors (10455920).

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

7221520 is a wasteful number, since it uses less digits than its factorization.

7221520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4783 (or 4777 counting only the distinct ones).

The product of its (nonzero) digits is 280, while the sum is 19.

The square root of 7221520 is about 2687.2885963365. The cubic root of 7221520 is about 193.2900682682.

Adding to 7221520 its reverse (251227), we get a palindrome (7472747).

The spelling of 7221520 in words is "seven million, two hundred twenty-one thousand, five hundred twenty".