10721609 has 4 divisors (see below), whose sum is σ = 10739604. Its totient is φ = 10703616.

The previous prime is 10721603. The next prime is 10721621. The reversal of 10721609 is 90612701.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90612701 = 4703 ⋅19267.

It can be written as a sum of positive squares in 2 ways, for example, as 462400 + 10259209 = 680^2 + 3203^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-10721609 is a prime.

It is a super-2 number, since 2×10721609² = 229905799097762, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (10721603) 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, 8072 + ... + 9305.

It is an arithmetic number, because the mean of its divisors is an integer number (2684901).

Almost surely, 2^10721609 is an apocalyptic number.

It is an amenable number.

10721609 is a deficient number, since it is larger than the sum of its proper divisors (17995).

10721609 is an equidigital number, since it uses as much as digits as its factorization.

10721609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17994.

The product of its (nonzero) digits is 756, while the sum is 26.

The square root of 10721609 is about 3274.3868128247. The cubic root of 10721609 is about 220.5057853320.

The spelling of 10721609 in words is "ten million, seven hundred twenty-one thousand, six hundred nine".