1101085721 has 4 divisors (see below), whose sum is σ = 1101243444. Its totient is φ = 1100928000.

The previous prime is 1101085691. The next prime is 1101085723. The reversal of 1101085721 is 1275801011.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 297079696 + 804006025 = 17236^2 + 28355^2 .

It is a cyclic number.

It is not a de Polignac number, because 1101085721 - 2¹⁰ = 1101084697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1101085723) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 67880 + ... + 82521.

It is an arithmetic number, because the mean of its divisors is an integer number (275310861).

Almost surely, 2^1101085721 is an apocalyptic number.

It is an amenable number.

1101085721 is a deficient number, since it is larger than the sum of its proper divisors (157723).

1101085721 is an equidigital number, since it uses as much as digits as its factorization.

1101085721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 157722.

The product of its (nonzero) digits is 560, while the sum is 26.

The square root of 1101085721 is about 33182.6117266257. The cubic root of 1101085721 is about 1032.6196305053.

Adding to 1101085721 its reverse (1275801011), we get a palindrome (2376886732).

The spelling of 1101085721 in words is "one billion, one hundred one million, eighty-five thousand, seven hundred twenty-one".