1321212120 has 256 divisors, whose sum is σ = 4478976000. Its totient is φ = 309805056.

The previous prime is 1321212119. The next prime is 1321212149. The reversal of 1321212120 is 212121231.

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 1321212120.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 3449449 + ... + 3449831.

It is an arithmetic number, because the mean of its divisors is an integer number (17496000).

Almost surely, 2^1321212120 is an apocalyptic number.

1321212120 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 1321212120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2239488000).

1321212120 is an abundant number, since it is smaller than the sum of its proper divisors (3157763880).

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

1321212120 is a wasteful number, since it uses less digits than its factorization.

1321212120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 522 (or 518 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 15.

The square root of 1321212120 is about 36348.4816739297. The cubic root of 1321212120 is about 1097.2969776476.

Adding to 1321212120 its reverse (212121231), we get a palindrome (1533333351).

The spelling of 1321212120 in words is "one billion, three hundred twenty-one million, two hundred twelve thousand, one hundred twenty".