231990 has 64 divisors (see below), whose sum is σ = 656640. Its totient is φ = 51840.

The previous prime is 231967. The next prime is 232003. The reversal of 231990 is 99132.

It is a happy number.

231990 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 231990.

It is a congruent number.

It is an unprimeable number.

231990 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6252 + ... + 6288.

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

2²³¹⁹⁹⁰ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 231990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (328320).

231990 is an abundant number, since it is smaller than the sum of its proper divisors (424650).

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

231990 is a wasteful number, since it uses less digits than its factorization.

231990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77.

The product of its (nonzero) digits is 486, while the sum is 24.

The square root of 231990 is about 481.6534023548. The cubic root of 231990 is about 61.4454536514.

It can be divided in two parts, 231 and 990, that added together give a palindrome (1221).

The spelling of 231990 in words is "two hundred thirty-one thousand, nine hundred ninety".