20813839 has 2 divisors, whose sum is σ = 20813840. Its totient is φ = 20813838.

The previous prime is 20813813. The next prime is 20813879. The reversal of 20813839 is 93831802.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20813839 - 2¹³ = 20805647 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20813879) 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, 10406919 + 10406920.

It is an arithmetic number, because the mean of its divisors is an integer number (10406920).

Almost surely, 2^20813839 is an apocalyptic number.

20813839 is a deficient number, since it is larger than the sum of its proper divisors (1).

20813839 is an equidigital number, since it uses as much as digits as its factorization.

20813839 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 10368, while the sum is 34.

The square root of 20813839 is about 4562.2186488593. The cubic root of 20813839 is about 275.0747521304.

The spelling of 20813839 in words is "twenty million, eight hundred thirteen thousand, eight hundred thirty-nine".