1321201320 has 64 divisors (see below), whose sum is σ = 3994859520. Its totient is φ = 349542144.

The previous prime is 1321201303. The next prime is 1321201339. The reversal of 1321201320 is 231021231.

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 1321201320.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 28107 + ... + 58586.

It is an arithmetic number, because the mean of its divisors is an integer number (62419680).

Almost surely, 2^1321201320 is an apocalyptic number.

1321201320 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1321201320 is an abundant number, since it is smaller than the sum of its proper divisors (2673658200).

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

1321201320 is a wasteful number, since it uses less digits than its factorization.

1321201320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 86834 (or 86830 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 15.

The square root of 1321201320 is about 36348.3331117123. Note that the first 3 decimals coincide. The cubic root of 1321201320 is about 1097.2939877568.

Adding to 1321201320 its reverse (231021231), we get a palindrome (1552222551).

The spelling of 1321201320 in words is "one billion, three hundred twenty-one million, two hundred one thousand, three hundred twenty".