1181365640 has 128 divisors (see below), whose sum is σ = 3283096320. Its totient is φ = 372556800.

The previous prime is 1181365609. The next prime is 1181365681. The reversal of 1181365640 is 465631811.

It is a Cunningham number, because it is equal to 34371²-1.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a self number, because there is not a number n which added to its sum of digits gives 1181365640.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1786910 + ... + 1787570.

It is an arithmetic number, because the mean of its divisors is an integer number (25649190).

Almost surely, 2^1181365640 is an apocalyptic number.

1181365640 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 1181365640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1641548160).

1181365640 is an abundant number, since it is smaller than the sum of its proper divisors (2101730680).

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

1181365640 is a wasteful number, since it uses less digits than its factorization.

1181365640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1183 (or 1179 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 35.

The square root of 1181365640 is about 34370.9999854529. Note that the first 4 decimals coincide. The cubic root of 1181365640 is about 1057.1293039064.

The spelling of 1181365640 in words is "one billion, one hundred eighty-one million, three hundred sixty-five thousand, six hundred forty".