1555221 has 8 divisors (see below), whose sum is σ = 2129824. Its totient is φ = 1008720.

The previous prime is 1555199. The next prime is 1555223. The reversal of 1555221 is 1225551.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1555221 - 2⁵ = 1555189 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1555223) 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 7 ways as a sum of consecutive naturals, for example, 6895 + ... + 7116.

It is an arithmetic number, because the mean of its divisors is an integer number (266228).

2^1555221 is an apocalyptic number.

It is an amenable number.

1555221 is a deficient number, since it is larger than the sum of its proper divisors (574603).

1555221 is a wasteful number, since it uses less digits than its factorization.

1555221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14051.

The product of its digits is 500, while the sum is 21.

The square root of 1555221 is about 1247.0850011126. The cubic root of 1555221 is about 115.8592476338.

The spelling of 1555221 in words is "one million, five hundred fifty-five thousand, two hundred twenty-one".