43999 has 4 divisors (see below), whose sum is σ = 45936. Its totient is φ = 42064.

The previous prime is 43997. The next prime is 44017. The reversal of 43999 is 99934.

43999 = T₅₀ + T₅₁ + ... + T₇₂.

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 43999 - 2¹ = 43997 is a prime.

It is a Duffinian number.

43999 is a modest number, since divided by 999 gives 43 as remainder.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (43991) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 934 + ... + 979.

It is an arithmetic number, because the mean of its divisors is an integer number (11484).

2⁴³⁹⁹⁹ is an apocalyptic number.

43999 is a deficient number, since it is larger than the sum of its proper divisors (1937).

43999 is a wasteful number, since it uses less digits than its factorization.

43999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1936.

The product of its digits is 8748, while the sum is 34.

The square root of 43999 is about 209.7593859640. The cubic root of 43999 is about 35.3032159006.

The spelling of 43999 in words is "forty-three thousand, nine hundred ninety-nine".