1091089440 has 576 divisors, whose sum is σ = 4667120640. Its totient is φ = 235146240.

The previous prime is 1091089397. The next prime is 1091089451. The reversal of 1091089440 is 449801901.

1091089440 is a `hidden beast` number, since 109 + 108 + 9 + 440 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 1091089395 and 1091089404.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 5170935 + ... + 5171145.

It is an arithmetic number, because the mean of its divisors is an integer number (8102640).

Almost surely, 2^1091089440 is an apocalyptic number.

1091089440 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 1091089440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2333560320).

1091089440 is an abundant number, since it is smaller than the sum of its proper divisors (3576031200).

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

1091089440 is a wasteful number, since it uses less digits than its factorization.

1091089440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 267 (or 247 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 36.

The square root of 1091089440 is about 33031.6430109070. The cubic root of 1091089440 is about 1029.4852236475.

The spelling of 1091089440 in words is "one billion, ninety-one million, eighty-nine thousand, four hundred forty".