1388821 has 8 divisors (see below), whose sum is σ = 1596800. Its totient is φ = 1183248.

The previous prime is 1388819. The next prime is 1388837. The reversal of 1388821 is 1288831.

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

It is a cyclic number.

It is not a de Polignac number, because 1388821 - 2¹ = 1388819 is a prime.

It is a Duffinian number.

1388821 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1388021) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 895 + ... + 1891.

It is an arithmetic number, because the mean of its divisors is an integer number (199600).

2^1388821 is an apocalyptic number.

It is an amenable number.

1388821 is a deficient number, since it is larger than the sum of its proper divisors (207979).

1388821 is an equidigital number, since it uses as much as digits as its factorization.

1388821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1203.

The product of its digits is 3072, while the sum is 31.

The square root of 1388821 is about 1178.4824988094. The cubic root of 1388821 is about 111.5703404350.

It can be divided in two parts, 1388 and 821, that added together give a square (2209 = 47²).

The spelling of 1388821 in words is "one million, three hundred eighty-eight thousand, eight hundred twenty-one".