1091091220 has 12 divisors (see below), whose sum is σ = 2291291604. Its totient is φ = 436436480.

The previous prime is 1091091173. The next prime is 1091091223. The reversal of 1091091220 is 221901901.

It can be written as a sum of positive squares in 2 ways, for example, as 373494276 + 717596944 = 19326^2 + 26788^2 .

It is a super-2 number, since 2×1091091220² = 2380960100722176800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1091091223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 27277261 + ... + 27277300.

It is an arithmetic number, because the mean of its divisors is an integer number (190940967).

Almost surely, 2^1091091220 is an apocalyptic number.

1091091220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1091091220 is an abundant number, since it is smaller than the sum of its proper divisors (1200200384).

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

1091091220 is a wasteful number, since it uses less digits than its factorization.

1091091220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54554570 (or 54554568 counting only the distinct ones).

The product of its (nonzero) digits is 324, while the sum is 25.

The square root of 1091091220 is about 33031.6699547571. The cubic root of 1091091220 is about 1029.4857834802.

The spelling of 1091091220 in words is "one billion, ninety-one million, ninety-one thousand, two hundred twenty".