109991000 has 128 divisors (see below), whose sum is σ = 310003200. Its totient is φ = 35683200.

The previous prime is 109990963. The next prime is 109991027. The reversal of 109991000 is 199901.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 132587 + ... + 133413.

It is an arithmetic number, because the mean of its divisors is an integer number (2421900).

Almost surely, 2^109991000 is an apocalyptic number.

109991000 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 109991000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (155001600).

109991000 is an abundant number, since it is smaller than the sum of its proper divisors (200012200).

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

109991000 is a wasteful number, since it uses less digits than its factorization.

109991000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 874 (or 860 counting only the distinct ones).

The product of its (nonzero) digits is 729, while the sum is 29.

The square root of 109991000 is about 10487.6594147598. The cubic root of 109991000 is about 479.1289178412.

The spelling of 109991000 in words is "one hundred nine million, nine hundred ninety-one thousand".