1388221 has 4 divisors (see below), whose sum is σ = 1398492. Its totient is φ = 1377952.

The previous prime is 1388183. The next prime is 1388227. The reversal of 1388221 is 1228831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1228831 = 193 ⋅6367.

It can be written as a sum of positive squares in 2 ways, for example, as 972196 + 416025 = 986^2 + 645^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1388221 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1388227) 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 3 ways as a sum of consecutive naturals, for example, 4930 + ... + 5203.

It is an arithmetic number, because the mean of its divisors is an integer number (349623).

2^1388221 is an apocalyptic number.

It is an amenable number.

1388221 is a deficient number, since it is larger than the sum of its proper divisors (10271).

1388221 is a wasteful number, since it uses less digits than its factorization.

1388221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10270.

The product of its digits is 768, while the sum is 25.

The square root of 1388221 is about 1178.2279066462. The cubic root of 1388221 is about 111.5542712064.

The spelling of 1388221 in words is "one million, three hundred eighty-eight thousand, two hundred twenty-one".