2578221 has 6 divisors (see below), whose sum is σ = 3724110. Its totient is φ = 1718808.

The previous prime is 2578217. The next prime is 2578249. The reversal of 2578221 is 1228752.

It can be written as a sum of positive squares in only one way, i.e., 1550025 + 1028196 = 1245^2 + 1014^2 .

It is not a de Polignac number, because 2578221 - 2² = 2578217 is a prime.

2578221 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2578201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 143226 + ... + 143243.

It is an arithmetic number, because the mean of its divisors is an integer number (620685).

2^2578221 is an apocalyptic number.

It is an amenable number.

2578221 is a deficient number, since it is larger than the sum of its proper divisors (1145889).

2578221 is a wasteful number, since it uses less digits than its factorization.

2578221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 286475 (or 286472 counting only the distinct ones).

The product of its digits is 2240, while the sum is 27.

The square root of 2578221 is about 1605.6839664143. The cubic root of 2578221 is about 137.1218657418.

The spelling of 2578221 in words is "two million, five hundred seventy-eight thousand, two hundred twenty-one".