23040821 has 4 divisors (see below), whose sum is σ = 23130732. Its totient is φ = 22950912.

The previous prime is 23040803. The next prime is 23040833. The reversal of 23040821 is 12804032.

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 22221796 + 819025 = 4714^2 + 905^2 .

It is a cyclic number.

It is not a de Polignac number, because 23040821 - 2¹⁴ = 23024437 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 23040793 and 23040802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (23040881) 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, 44570 + ... + 45083.

It is an arithmetic number, because the mean of its divisors is an integer number (5782683).

Almost surely, 2^23040821 is an apocalyptic number.

It is an amenable number.

23040821 is a deficient number, since it is larger than the sum of its proper divisors (89911).

23040821 is an equidigital number, since it uses as much as digits as its factorization.

23040821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 89910.

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 23040821 is about 4800.0855200715. The cubic root of 23040821 is about 284.5548441911.

Adding to 23040821 its reverse (12804032), we get a palindrome (35844853).

The spelling of 23040821 in words is "twenty-three million, forty thousand, eight hundred twenty-one".