20121220320 has 48 divisors (see below), whose sum is σ = 63381845520. Its totient is φ = 5365658624.

The previous prime is 20121220319. The next prime is 20121220321. The reversal of 20121220320 is 2302212102.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (20121220319) and next prime (20121220321).

It is a tau number, because it is divible by the number of its divisors (48).

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 20121220320.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20121220321) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20959125 + ... + 20960084.

It is an arithmetic number, because the mean of its divisors is an integer number (1320455115).

Almost surely, 2^20121220320 is an apocalyptic number.

20121220320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20121220320 is an abundant number, since it is smaller than the sum of its proper divisors (43260625200).

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

20121220320 is a wasteful number, since it uses less digits than its factorization.

20121220320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41919227 (or 41919219 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 15.

Adding to 20121220320 its reverse (2302212102), we get a palindrome (22423432422).

The spelling of 20121220320 in words is "twenty billion, one hundred twenty-one million, two hundred twenty thousand, three hundred twenty".