121399 has 4 divisors (see below), whose sum is σ = 123136. Its totient is φ = 119664.

The previous prime is 121379. The next prime is 121403. The reversal of 121399 is 993121.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 121399 - 2⁵ = 121367 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (121309) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 759 + ... + 904.

It is an arithmetic number, because the mean of its divisors is an integer number (30784).

2¹²¹³⁹⁹ is an apocalyptic number.

121399 is a deficient number, since it is larger than the sum of its proper divisors (1737).

121399 is an equidigital number, since it uses as much as digits as its factorization.

121399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1736.

The product of its digits is 486, while the sum is 25.

The square root of 121399 is about 348.4235927718. The cubic root of 121399 is about 49.5151808691.

The spelling of 121399 in words is "one hundred twenty-one thousand, three hundred ninety-nine".