23131021221 has 48 divisors (see below), whose sum is σ = 41931921408. Its totient is φ = 11936484000.

The previous prime is 23131021217. The next prime is 23131021231. The reversal of 23131021221 is 12212013132.

23131021221 is a `hidden beast` number, since 231 + 310 + 2 + 122 + 1 = 666.

It is not a de Polignac number, because 23131021221 - 2² = 23131021217 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 23131021194 and 23131021203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (23131021231) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 5881 + ... + 215166.

It is an arithmetic number, because the mean of its divisors is an integer number (873581696).

Almost surely, 2^23131021221 is an apocalyptic number.

23131021221 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

23131021221 is a deficient number, since it is larger than the sum of its proper divisors (18800900187).

23131021221 is a wasteful number, since it uses less digits than its factorization.

23131021221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 221222 (or 221219 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 23131021221 its reverse (12212013132), we get a palindrome (35343034353).

The spelling of 23131021221 in words is "twenty-three billion, one hundred thirty-one million, twenty-one thousand, two hundred twenty-one".