1389921 has 16 divisors (see below), whose sum is σ = 2017344. Its totient is φ = 846144.

The previous prime is 1389919. The next prime is 1389943. The reversal of 1389921 is 1299831.

It is not a de Polignac number, because 1389921 - 2¹ = 1389919 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1389911) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6010 + ... + 6236.

It is an arithmetic number, because the mean of its divisors is an integer number (126084).

2^1389921 is an apocalyptic number.

1389921 is the 681-st octagonal number.

It is an amenable number.

1389921 is a deficient number, since it is larger than the sum of its proper divisors (627423).

1389921 is a wasteful number, since it uses less digits than its factorization.

1389921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 400.

The product of its digits is 3888, while the sum is 33.

The square root of 1389921 is about 1178.9491083164. The cubic root of 1389921 is about 111.5997886714.

The spelling of 1389921 in words is "one million, three hundred eighty-nine thousand, nine hundred twenty-one".