20121823 has 2 divisors, whose sum is σ = 20121824. Its totient is φ = 20121822.

The previous prime is 20121811. The next prime is 20121839. The reversal of 20121823 is 32812102.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20121823 - 2⁵ = 20121791 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20121823.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20121623) 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, 10060911 + 10060912.

It is an arithmetic number, because the mean of its divisors is an integer number (10060912).

Almost surely, 2^20121823 is an apocalyptic number.

20121823 is a deficient number, since it is larger than the sum of its proper divisors (1).

20121823 is an equidigital number, since it uses as much as digits as its factorization.

20121823 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 192, while the sum is 19.

The square root of 20121823 is about 4485.7355026796. The cubic root of 20121823 is about 271.9917772529.

Adding to 20121823 its reverse (32812102), we get a palindrome (52933925).

The spelling of 20121823 in words is "twenty million, one hundred twenty-one thousand, eight hundred twenty-three".