1091001820 has 24 divisors (see below), whose sum is σ = 2334334464. Its totient is φ = 428166336.

The previous prime is 1091001797. The next prime is 1091001839. The reversal of 1091001820 is 281001901.

It is a junction number, because it is equal to n+sod(n) for n = 1091001791 and 1091001800.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 513564 + ... + 515683.

It is an arithmetic number, because the mean of its divisors is an integer number (97263936).

Almost surely, 2^1091001820 is an apocalyptic number.

1091001820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1091001820 is an abundant number, since it is smaller than the sum of its proper divisors (1243332644).

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

1091001820 is a wasteful number, since it uses less digits than its factorization.

1091001820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1029309 (or 1029307 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 22.

The square root of 1091001820 is about 33030.3166802863. The cubic root of 1091001820 is about 1029.4576652865.

The spelling of 1091001820 in words is "one billion, ninety-one million, one thousand, eight hundred twenty".