7555221 has 8 divisors (see below), whose sum is σ = 11192960. Its totient is φ = 5036796.

The previous prime is 7555211. The next prime is 7555243. The reversal of 7555221 is 1225557.

It is a happy number.

It is not a de Polignac number, because 7555221 - 2⁵ = 7555189 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27), and also a Moran number because the ratio is a prime number: 279823 = 7555221 / (7 + 5 + 5 + 5 + 2 + 2 + 1).

It is a Duffinian number.

It is a nialpdrome in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7555211) 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, 139885 + ... + 139938.

It is an arithmetic number, because the mean of its divisors is an integer number (1399120).

Almost surely, 2^7555221 is an apocalyptic number.

It is an amenable number.

7555221 is a deficient number, since it is larger than the sum of its proper divisors (3637739).

7555221 is a wasteful number, since it uses less digits than its factorization.

7555221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 279832 (or 279826 counting only the distinct ones).

The product of its digits is 3500, while the sum is 27.

The square root of 7555221 is about 2748.6762268408. The cubic root of 7555221 is about 196.2226142700. Note that the first 3 decimals are identical.

It can be divided in two parts, 7555 and 221, that added together give a 5-th power (7776 = 6⁵).

The spelling of 7555221 in words is "seven million, five hundred fifty-five thousand, two hundred twenty-one".