23390821 has 2 divisors, whose sum is σ = 23390822. Its totient is φ = 23390820.

The previous prime is 23390813. The next prime is 23390837. The reversal of 23390821 is 12809332.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 23174596 + 216225 = 4814^2 + 465^2 .

It is a cyclic number.

It is not a de Polignac number, because 23390821 - 2³ = 23390813 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 23390821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (23390021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11695410 + 11695411.

It is an arithmetic number, because the mean of its divisors is an integer number (11695411).

Almost surely, 2^23390821 is an apocalyptic number.

It is an amenable number.

23390821 is a deficient number, since it is larger than the sum of its proper divisors (1).

23390821 is an equidigital number, since it uses as much as digits as its factorization.

23390821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 23390821 is about 4836.4057935620. The cubic root of 23390821 is about 285.9884464011.

The spelling of 23390821 in words is "twenty-three million, three hundred ninety thousand, eight hundred twenty-one".