23307821 has 2 divisors, whose sum is σ = 23307822. Its totient is φ = 23307820.

The previous prime is 23307787. The next prime is 23307847. The reversal of 23307821 is 12870332.

It is an a-pointer prime, because the next prime (23307847) can be obtained adding 23307821 to its sum of digits (26).

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 23174596 + 133225 = 4814^2 + 365^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-23307821 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is equal to p_1466405 and since 23307821 and 1466405 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (23307881) 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, 11653910 + 11653911.

It is an arithmetic number, because the mean of its divisors is an integer number (11653911).

Almost surely, 2^23307821 is an apocalyptic number.

It is an amenable number.

23307821 is a deficient number, since it is larger than the sum of its proper divisors (1).

23307821 is an equidigital number, since it uses as much as digits as its factorization.

23307821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2016, while the sum is 26.

The square root of 23307821 is about 4827.8174157687. The cubic root of 23307821 is about 285.6497783297.

The spelling of 23307821 in words is "twenty-three million, three hundred seven thousand, eight hundred twenty-one".