20051813 has 2 divisors, whose sum is σ = 20051814. Its totient is φ = 20051812.

The previous prime is 20051767. The next prime is 20051819. The reversal of 20051813 is 31815002.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14010049 + 6041764 = 3743^2 + 2458^2 .

It is a cyclic number.

It is not a de Polignac number, because 20051813 - 2²² = 15857509 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20051819) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10025906 + 10025907.

It is an arithmetic number, because the mean of its divisors is an integer number (10025907).

Almost surely, 2^20051813 is an apocalyptic number.

It is an amenable number.

20051813 is a deficient number, since it is larger than the sum of its proper divisors (1).

20051813 is an equidigital number, since it uses as much as digits as its factorization.

20051813 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 240, while the sum is 20.

The square root of 20051813 is about 4477.9250775331. The cubic root of 20051813 is about 271.6759630644.

Adding to 20051813 its reverse (31815002), we get a palindrome (51866815).

The spelling of 20051813 in words is "twenty million, fifty-one thousand, eight hundred thirteen".