1323121220 has 48 divisors (see below), whose sum is σ = 2952609408. Its totient is φ = 496320000.

The previous prime is 1323121213. The next prime is 1323121229. The reversal of 1323121220 is 221213231.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is not an unprimeable number, because it can be changed into a prime (1323121229) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 89345 + ... + 103095.

It is an arithmetic number, because the mean of its divisors is an integer number (61512696).

Almost surely, 2^1323121220 is an apocalyptic number.

1323121220 is a gapful number since it is divisible by the number (10) 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 1323121220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1476304704).

1323121220 is an abundant number, since it is smaller than the sum of its proper divisors (1629488188).

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

1323121220 is a wasteful number, since it uses less digits than its factorization.

1323121220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14060 (or 14058 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 1323121220 is about 36374.7332636268. The cubic root of 1323121220 is about 1097.8252404061.

Adding to 1323121220 its reverse (221213231), we get a palindrome (1544334451).

The spelling of 1323121220 in words is "one billion, three hundred twenty-three million, one hundred twenty-one thousand, two hundred twenty".