23213131221 has 16 divisors (see below), whose sum is σ = 35379721728. Its totient is φ = 13261897200.

The previous prime is 23213131189. The next prime is 23213131237. The reversal of 23213131221 is 12213131232.

It is not a de Polignac number, because 23213131221 - 2⁵ = 23213131189 is a prime.

It is a super-2 number, since 2×23213131221² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (23213131241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8535 + ... + 215636.

It is an arithmetic number, because the mean of its divisors is an integer number (2211232608).

Almost surely, 2^23213131221 is an apocalyptic number.

23213131221 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

23213131221 is a deficient number, since it is larger than the sum of its proper divisors (12166590507).

23213131221 is a wasteful number, since it uses less digits than its factorization.

23213131221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 229112.

The product of its digits is 432, while the sum is 21.

Adding to 23213131221 its reverse (12213131232), we get a palindrome (35426262453).

The spelling of 23213131221 in words is "twenty-three billion, two hundred thirteen million, one hundred thirty-one thousand, two hundred twenty-one".