1091909091 has 24 divisors (see below), whose sum is σ = 1823851344. Its totient is φ = 575951040.

The previous prime is 1091909069. The next prime is 1091909179. The reversal of 1091909091 is 1909091901.

It is not a de Polignac number, because 1091909091 - 2¹⁴ = 1091892707 is a prime.

It is a hoax number, since the sum of its digits (39) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is not an unprimeable number, because it can be changed into a prime (1091909011) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 283780 + ... + 287601.

It is an arithmetic number, because the mean of its divisors is an integer number (75993806).

Almost surely, 2^1091909091 is an apocalyptic number.

1091909091 is a deficient number, since it is larger than the sum of its proper divisors (731942253).

1091909091 is a wasteful number, since it uses less digits than its factorization.

1091909091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 571411 (or 571404 counting only the distinct ones).

The product of its (nonzero) digits is 6561, while the sum is 39.

The square root of 1091909091 is about 33044.0477393433. The cubic root of 1091909091 is about 1029.7429499626.

The spelling of 1091909091 in words is "one billion, ninety-one million, nine hundred nine thousand, ninety-one".