1191027840 has 128 divisors (see below), whose sum is σ = 3850312320. Its totient is φ = 313098240.

The previous prime is 1191027829. The next prime is 1191027841. The reversal of 1191027840 is 487201911.

It is a tau number, because it is divible by the number of its divisors (128).

It is not an unprimeable number, because it can be changed into a prime (1191027841) 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, 131952 + ... + 140688.

It is an arithmetic number, because the mean of its divisors is an integer number (30080565).

Almost surely, 2^1191027840 is an apocalyptic number.

1191027840 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 1191027840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1925156160).

1191027840 is an abundant number, since it is smaller than the sum of its proper divisors (2659284480).

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

1191027840 is an equidigital number, since it uses as much as digits as its factorization.

1191027840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8830 (or 8818 counting only the distinct ones).

The product of its (nonzero) digits is 4032, while the sum is 33.

The square root of 1191027840 is about 34511.2712023188. The cubic root of 1191027840 is about 1060.0035125076.

The spelling of 1191027840 in words is "one billion, one hundred ninety-one million, twenty-seven thousand, eight hundred forty".