23121212220 has 72 divisors (see below), whose sum is σ = 72552785760. Its totient is φ = 5953046400.

The previous prime is 23121212209. The next prime is 23121212221. The reversal of 23121212220 is 2221212132.

23121212220 is a `hidden beast` number, since 231 + 2 + 1 + 212 + 220 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 23121212193 and 23121212202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (23121212221) 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, 2209456 + ... + 2219895.

It is an arithmetic number, because the mean of its divisors is an integer number (1007677580).

Almost surely, 2^23121212220 is an apocalyptic number.

23121212220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

23121212220 is an abundant number, since it is smaller than the sum of its proper divisors (49431573540).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

23121212220 is a wasteful number, since it uses less digits than its factorization.

23121212220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4429395 (or 4429390 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 18.

Adding to 23121212220 its reverse (2221212132), we get a palindrome (25342424352).

The spelling of 23121212220 in words is "twenty-three billion, one hundred twenty-one million, two hundred twelve thousand, two hundred twenty".