1211989320 has 96 divisors (see below), whose sum is σ = 3956584320. Its totient is φ = 321751680.

The previous prime is 1211989253. The next prime is 1211989327. The reversal of 1211989320 is 239891121.

It is a super-2 number, since 2×1211989320² = 2937836223588124800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (1211989327) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 74305 + ... + 89135.

It is an arithmetic number, because the mean of its divisors is an integer number (41214420).

Almost surely, 2^1211989320 is an apocalyptic number.

1211989320 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 1211989320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1978292160).

1211989320 is an abundant number, since it is smaller than the sum of its proper divisors (2744595000).

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

1211989320 is a wasteful number, since it uses less digits than its factorization.

1211989320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15075 (or 15068 counting only the distinct ones).

The product of its (nonzero) digits is 7776, while the sum is 36.

The square root of 1211989320 is about 34813.6369832283. The cubic root of 1211989320 is about 1066.1858905383.

The spelling of 1211989320 in words is "one billion, two hundred eleven million, nine hundred eighty-nine thousand, three hundred twenty".