20121223440 has 160 divisors (see below), whose sum is σ = 65722936320. Its totient is φ = 5078287872.

The previous prime is 20121223429. The next prime is 20121223471. The reversal of 20121223440 is 4432212102.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7600197 + ... + 7602843.

It is an arithmetic number, because the mean of its divisors is an integer number (410768352).

Almost surely, 2^20121223440 is an apocalyptic number.

20121223440 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 20121223440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32861468160).

20121223440 is an abundant number, since it is smaller than the sum of its proper divisors (45601712880).

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

20121223440 is a wasteful number, since it uses less digits than its factorization.

20121223440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4349 (or 4343 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 21.

Adding to 20121223440 its reverse (4432212102), we get a palindrome (24553435542).

The spelling of 20121223440 in words is "twenty billion, one hundred twenty-one million, two hundred twenty-three thousand, four hundred forty".