40399 has 4 divisors (see below), whose sum is σ = 41040. Its totient is φ = 39760.

The previous prime is 40387. The next prime is 40423. The reversal of 40399 is 99304.

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

It is not a de Polignac number, because 40399 - 2⁹ = 39887 is a prime.

It is a Duffinian number.

40399 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (40099) 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, 214 + ... + 355.

It is an arithmetic number, because the mean of its divisors is an integer number (10260).

2⁴⁰³⁹⁹ is an apocalyptic number.

40399 is a deficient number, since it is larger than the sum of its proper divisors (641).

40399 is an equidigital number, since it uses as much as digits as its factorization.

40399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 640.

The product of its (nonzero) digits is 972, while the sum is 25.

The square root of 40399 is about 200.9950248140. The cubic root of 40399 is about 34.3128563184.

The spelling of 40399 in words is "forty thousand, three hundred ninety-nine".