10821809 has 8 divisors (see below), whose sum is σ = 11524968. Its totient is φ = 10126080.

The previous prime is 10821781. The next prime is 10821829. The reversal of 10821809 is 90812801.

It can be written as a sum of positive squares in 4 ways, for example, as 2411809 + 8410000 = 1553^2 + 2900^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 10821809 - 2¹² = 10817713 is a prime.

It is a super-2 number, since 2×10821809² = 234223100064962, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (10821829) 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, 1319 + ... + 4835.

It is an arithmetic number, because the mean of its divisors is an integer number (1440621).

Almost surely, 2^10821809 is an apocalyptic number.

It is an amenable number.

10821809 is a deficient number, since it is larger than the sum of its proper divisors (703159).

10821809 is a wasteful number, since it uses less digits than its factorization.

10821809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3715.

The product of its (nonzero) digits is 1152, while the sum is 29.

The square root of 10821809 is about 3289.6518052827. The cubic root of 10821809 is about 221.1905769960.

The spelling of 10821809 in words is "ten million, eight hundred twenty-one thousand, eight hundred nine".