1550221 has 2 divisors, whose sum is σ = 1550222. Its totient is φ = 1550220.

The previous prime is 1550209. The next prime is 1550231. The reversal of 1550221 is 1220551.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1550025 + 196 = 1245^2 + 14^2 .

It is a cyclic number.

It is not a de Polignac number, because 1550221 - 2¹³ = 1542029 is a prime.

1550221 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 1550195 and 1550204.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1550231) 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 as a sum of consecutive naturals, namely, 775110 + 775111.

It is an arithmetic number, because the mean of its divisors is an integer number (775111).

2^1550221 is an apocalyptic number.

It is an amenable number.

1550221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1550221 is an equidigital number, since it uses as much as digits as its factorization.

1550221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 100, while the sum is 16.

The square root of 1550221 is about 1245.0787123712. The cubic root of 1550221 is about 115.7349527249.

Adding to 1550221 its reverse (1220551), we get a palindrome (2770772).

It can be divided in two parts, 1550 and 221, that added together give a palindrome (1771).

The spelling of 1550221 in words is "one million, five hundred fifty thousand, two hundred twenty-one".