231221000 has 64 divisors (see below), whose sum is σ = 550368000. Its totient is φ = 90897600.

The previous prime is 231220999. The next prime is 231221009. The reversal of 231221000 is 122132.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (231221009) 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 15 ways as a sum of consecutive naturals, for example, 57041 + ... + 60959.

It is an arithmetic number, because the mean of its divisors is an integer number (8599500).

Almost surely, 2^231221000 is an apocalyptic number.

231221000 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 231221000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (275184000).

231221000 is an abundant number, since it is smaller than the sum of its proper divisors (319147000).

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

231221000 is a wasteful number, since it uses less digits than its factorization.

231221000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3999 (or 3985 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 11.

The square root of 231221000 is about 15205.9527817233. The cubic root of 231221000 is about 613.7748540561.

Adding to 231221000 its reverse (122132), we get a palindrome (231343132).

The spelling of 231221000 in words is "two hundred thirty-one million, two hundred twenty-one thousand".