231001221 has 24 divisors (see below), whose sum is σ = 356376160. Its totient is φ = 132628320.

The previous prime is 231001187. The next prime is 231001223. The reversal of 231001221 is 122100132.

It is not a de Polignac number, because 231001221 - 2²¹ = 228904069 is a prime.

231001221 is a modest number, since divided by 1221 gives 231 as remainder.

It is a junction number, because it is equal to n+sod(n) for n = 231001197 and 231001206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (231001223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 9850 + ... + 23643.

Almost surely, 2^231001221 is an apocalyptic number.

It is an amenable number.

231001221 is a deficient number, since it is larger than the sum of its proper divisors (125374939).

231001221 is a wasteful number, since it uses less digits than its factorization.

231001221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33537 (or 33526 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 231001221 is about 15198.7243214686. The cubic root of 231001221 is about 613.5803250325.

Adding to 231001221 its reverse (122100132), we get a palindrome (353101353).

The spelling of 231001221 in words is "two hundred thirty-one million, one thousand, two hundred twenty-one".