1399 has 2 divisors, whose sum is σ = 1400.
Its totient is φ = 1398.
The previous prime is 1381. The next prime is 1409. The reversal of 1399 is 9931.
Subtracting from 1399 its product of digits (243), we obtain a square (1156 = 342).
It can be divided in two parts, 1 and 399, that added together give a square (400 = 202).
1399 is nontrivially palindromic in base 13.
1399 is an esthetic number in base 12, because in such base its adjacent digits differ by 1.
It is a strong prime.
It is an emirp because it is prime and its reverse (9931) is a distict prime.
It is a cyclic number.
It is not a de Polignac number, because 1399 - 25 = 1367 is a prime.
It is a Chen prime.
1399 is an undulating number in base 13.
1399 is a modest number, since divided by 99 gives 13 as remainder.
It is a plaindrome in base 8, base 10 and base 16.
It is a nialpdrome in base 12.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (1319) by changing a digit.
It is a good prime.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 699 + 700.
It is an arithmetic number, because the mean of its divisors is an integer number (700).
21399 is an apocalyptic number.
1399 is a deficient number, since it is larger than the sum of its proper divisors (1).
1399 is an equidigital number, since it uses as much as digits as its factorization.
1399 is an evil number, because the sum of its binary digits is even.
The product of its digits is 243, while the sum is 22.
The square root of 1399 is about 37.4032084185.
The cubic root of 1399 is about 11.1842252413.
The spelling of 1399 in words is "one thousand, three hundred ninety-nine".