1109721 has 8 divisors (see below), whose sum is σ = 1501984. Its totient is φ = 728640.

The previous prime is 1109663. The next prime is 1109723. The reversal of 1109721 is 1279011.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 1109721 - 2¹⁰ = 1108697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1109723) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2560 + ... + 2961.

It is an arithmetic number, because the mean of its divisors is an integer number (187748).

2^1109721 is an apocalyptic number.

It is an amenable number.

1109721 is a deficient number, since it is larger than the sum of its proper divisors (392263).

1109721 is an equidigital number, since it uses as much as digits as its factorization.

1109721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5591.

The product of its (nonzero) digits is 126, while the sum is 21.

The square root of 1109721 is about 1053.4329594236. The cubic root of 1109721 is about 103.5312048550.

It can be divided in two parts, 1109 and 721, that added together give a triangular number (1830 = T₆₀).

The spelling of 1109721 in words is "one million, one hundred nine thousand, seven hundred twenty-one".