1321200000 has 288 divisors, whose sum is σ = 4765007520. Its totient is φ = 351360000.

The previous prime is 1321199977. The next prime is 1321200047. The reversal of 1321200000 is 21231.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (288).

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a congruent number.

It is an unprimeable number.

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 35 ways as a sum of consecutive naturals, for example, 3599817 + ... + 3600183.

It is an arithmetic number, because the mean of its divisors is an integer number (16545165).

Almost surely, 2^1321200000 is an apocalyptic number.

1321200000 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 1321200000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2382503760).

1321200000 is an abundant number, since it is smaller than the sum of its proper divisors (3443807520).

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

1321200000 is an frugal number, since it uses more digits than its factorization.

1321200000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 412 (or 377 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 9.

The square root of 1321200000 is about 36348.3149540663. The cubic root of 1321200000 is about 1097.2936223246.

Adding to 1321200000 its reverse (21231), we get a palindrome (1321221231).

The spelling of 1321200000 in words is "one billion, three hundred twenty-one million, two hundred thousand".