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1389 = 3463

1389 has 4 divisors (see below), whose sum is σ = 1856. Its totient is φ = 924.

The previous prime is 1381. The next prime is 1399. The reversal of 1389 is 9831.

1389 is nontrivially palindromic in base 12.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 1389 - 23 = 1381 is a prime.

It is an Ulam number.

It is a D-number.

It is a Duffinian number.

1389 is an undulating number in base 12.

1389 is a lucky number.

It is a plaindrome in base 8, base 10 and base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 229 + ... + 234.

It is an arithmetic number, because the mean of its divisors is an integer number (464).

It is an amenable number.

1389 is a deficient number, since it is larger than the sum of its proper divisors (467).

1389 is an equidigital number, since it uses as much as digits as its factorization.

1389 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 466.

The product of its digits is 216, while the sum is 21.

The square root of 1389 is about 37.2692903072. The cubic root of 1389 is about 11.1575133525.

The spelling of 1389 in words is "one thousand, three hundred eighty-nine".

Divisors: 1 3 463 1389