20542813 has 2 divisors, whose sum is σ = 20542814. Its totient is φ = 20542812.

The previous prime is 20542811. The next prime is 20542831. The reversal of 20542813 is 31824502.

Together with next prime (20542831) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19166884 + 1375929 = 4378^2 + 1173^2 .

It is a cyclic number.

It is not a de Polignac number, because 20542813 - 2¹ = 20542811 is a prime.

Together with 20542811, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20542811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10271406 + 10271407.

It is an arithmetic number, because the mean of its divisors is an integer number (10271407).

Almost surely, 2^20542813 is an apocalyptic number.

It is an amenable number.

20542813 is a deficient number, since it is larger than the sum of its proper divisors (1).

20542813 is an equidigital number, since it uses as much as digits as its factorization.

20542813 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1920, while the sum is 25.

The square root of 20542813 is about 4532.4180080835. The cubic root of 20542813 is about 273.8755761997.

The spelling of 20542813 in words is "twenty million, five hundred forty-two thousand, eight hundred thirteen".