7557221 has 6 divisors (see below), whose sum is σ = 8791110. Its totient is φ = 6477576.

The previous prime is 7557203. The next prime is 7557227. The reversal of 7557221 is 1227557.

It can be written as a sum of positive squares in only one way, i.e., 6964321 + 592900 = 2639^2 + 770^2 .

It is not a de Polignac number, because 7557221 - 2⁶ = 7557157 is a prime.

It is a super-2 number, since 2×7557221² = 114223178485682, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7557227) 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 5 ways as a sum of consecutive naturals, for example, 77066 + ... + 77163.

It is an arithmetic number, because the mean of its divisors is an integer number (1465185).

Almost surely, 2^7557221 is an apocalyptic number.

It is an amenable number.

7557221 is a deficient number, since it is larger than the sum of its proper divisors (1233889).

7557221 is a wasteful number, since it uses less digits than its factorization.

7557221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154243 (or 154236 counting only the distinct ones).

The product of its digits is 4900, while the sum is 29.

The square root of 7557221 is about 2749.0400142595. The cubic root of 7557221 is about 196.2399272691.

The spelling of 7557221 in words is "seven million, five hundred fifty-seven thousand, two hundred twenty-one".