20123813 has 2 divisors, whose sum is σ = 20123814. Its totient is φ = 20123812.

The previous prime is 20123809. The next prime is 20123843. The reversal of 20123813 is 31832102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19909444 + 214369 = 4462^2 + 463^2 .

It is a cyclic number.

It is not a de Polignac number, because 20123813 - 2² = 20123809 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20123843) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10061906 + 10061907.

It is an arithmetic number, because the mean of its divisors is an integer number (10061907).

Almost surely, 2^20123813 is an apocalyptic number.

It is an amenable number.

20123813 is a deficient number, since it is larger than the sum of its proper divisors (1).

20123813 is an equidigital number, since it uses as much as digits as its factorization.

20123813 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 20123813 is about 4485.9573114331. The cubic root of 20123813 is about 272.0007434019. Note that the first 3 decimals are identical.

Adding to 20123813 its reverse (31832102), we get a palindrome (51955915).

The spelling of 20123813 in words is "twenty million, one hundred twenty-three thousand, eight hundred thirteen".