231221403 has 24 divisors (see below), whose sum is σ = 404153568. Its totient is φ = 124353792.

The previous prime is 231221401. The next prime is 231221411. The reversal of 231221403 is 304122132.

It is not a de Polignac number, because 231221403 - 2¹ = 231221401 is a prime.

It is not an unprimeable number, because it can be changed into a prime (231221401) 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, 106876 + ... + 109017.

It is an arithmetic number, because the mean of its divisors is an integer number (16839732).

Almost surely, 2^231221403 is an apocalyptic number.

231221403 is a deficient number, since it is larger than the sum of its proper divisors (172932165).

231221403 is a wasteful number, since it uses less digits than its factorization.

231221403 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 215923 (or 215920 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 231221403 is about 15205.9660331069. The cubic root of 231221403 is about 613.7752106429.

Adding to 231221403 its reverse (304122132), we get a palindrome (535343535).

The spelling of 231221403 in words is "two hundred thirty-one million, two hundred twenty-one thousand, four hundred three".