23121220 has 24 divisors (see below), whose sum is σ = 48648600. Its totient is φ = 9230592.

The previous prime is 23121209. The next prime is 23121247. The reversal of 23121220 is 2212132.

It can be written as a sum of positive squares in 4 ways, for example, as 1721344 + 21399876 = 1312^2 + 4626^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 23121220.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15466 + ... + 16894.

It is an arithmetic number, because the mean of its divisors is an integer number (2027025).

Almost surely, 2^23121220 is an apocalyptic number.

23121220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

23121220 is an abundant number, since it is smaller than the sum of its proper divisors (25527380).

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

23121220 is a wasteful number, since it uses less digits than its factorization.

23121220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2247 (or 2245 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 23121220 is about 4808.4529736704. The cubic root of 23121220 is about 284.8854366670.

Adding to 23121220 its reverse (2212132), we get a palindrome (25333352).

The spelling of 23121220 in words is "twenty-three million, one hundred twenty-one thousand, two hundred twenty".