1091787840 has 504 divisors, whose sum is σ = 4463683224. Its totient is φ = 243302400.

The previous prime is 1091787793. The next prime is 1091787841. The reversal of 1091787840 is 487871901.

It can be written as a sum of positive squares in 4 ways, for example, as 71368704 + 1020419136 = 8448^2 + 31944^2 .

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1091787841) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 4530120 + ... + 4530360.

Almost surely, 2^1091787840 is an apocalyptic number.

1091787840 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 1091787840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2231841612).

1091787840 is an abundant number, since it is smaller than the sum of its proper divisors (3371895384).

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

1091787840 is a wasteful number, since it uses less digits than its factorization.

1091787840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 299 (or 275 counting only the distinct ones).

The product of its (nonzero) digits is 112896, while the sum is 45.

The square root of 1091787840 is about 33042.2130009477. The cubic root of 1091787840 is about 1029.7048326305.

The spelling of 1091787840 in words is "one billion, ninety-one million, seven hundred eighty-seven thousand, eight hundred forty".