20113123221 has 24 divisors (see below), whose sum is σ = 29777483736. Its totient is φ = 13074408960.

The previous prime is 20113123213. The next prime is 20113123343. The reversal of 20113123221 is 12232131102.

20113123221 is a `hidden beast` number, since 20 + 11 + 312 + 322 + 1 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 2186591121 + 17926532100 = 46761^2 + 133890^2 .

It is not a de Polignac number, because 20113123221 - 2³ = 20113123213 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20113123194 and 20113123203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20113123201) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 691651 + ... + 720143.

It is an arithmetic number, because the mean of its divisors is an integer number (1240728489).

Almost surely, 2^20113123221 is an apocalyptic number.

It is an amenable number.

20113123221 is a deficient number, since it is larger than the sum of its proper divisors (9664360515).

20113123221 is a wasteful number, since it uses less digits than its factorization.

20113123221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30453 (or 30450 counting only the distinct ones).

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

Adding to 20113123221 its reverse (12232131102), we get a palindrome (32345254323).

The spelling of 20113123221 in words is "twenty billion, one hundred thirteen million, one hundred twenty-three thousand, two hundred twenty-one".