23111220 has 144 divisors (see below), whose sum is σ = 75273408. Its totient is φ = 5253120.

The previous prime is 23111219. The next prime is 23111237. The reversal of 23111220 is 2211132.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 23111196 and 23111205.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 238212 + ... + 238308.

It is an arithmetic number, because the mean of its divisors is an integer number (522732).

Almost surely, 2^23111220 is an apocalyptic number.

23111220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 23111220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37636704).

23111220 is an abundant number, since it is smaller than the sum of its proper divisors (52162188).

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

23111220 is a wasteful number, since it uses less digits than its factorization.

23111220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 158 (or 137 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 23111220 is about 4807.4130257343. The cubic root of 23111220 is about 284.8443594635.

Adding to 23111220 its reverse (2211132), we get a palindrome (25322352).

It can be divided in two parts, 231112 and 20, that added together give a palindrome (231132).

The spelling of 23111220 in words is "twenty-three million, one hundred eleven thousand, two hundred twenty".