43890 has 64 divisors (see below), whose sum is σ = 138240. Its totient is φ = 8640.

The previous prime is 43889. The next prime is 43891. The reversal of 43890 is 9834.

43890 = T₅₆ + T₅₇ + ... + T₇₅.

It is an interprime number because it is at equal distance from previous prime (43889) and next prime (43891).

It is an Ulam number.

It is an alternating number because its digits alternate between even and odd.

It is a self number, because there is not a number n which added to its sum of digits gives 43890.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (43891) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2301 + ... + 2319.

It is an arithmetic number, because the mean of its divisors is an integer number (2160).

2⁴³⁸⁹⁰ is an apocalyptic number.

It is a pronic number, being equal to 209×210.

It is a practical number, because each smaller number is the sum of distinct divisors of 43890, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (69120).

43890 is an abundant number, since it is smaller than the sum of its proper divisors (94350).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

43890 is a wasteful number, since it uses less digits than its factorization.

43890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47.

The product of its (nonzero) digits is 864, while the sum is 24.

The square root of 43890 is about 209.4994033404. The cubic root of 43890 is about 35.2740392334.

It can be divided in two parts, 438 and 90, that added together give a triangular number (528 = T₃₂).

The spelling of 43890 in words is "forty-three thousand, eight hundred ninety".