20806259 has 2 divisors, whose sum is σ = 20806260. Its totient is φ = 20806258.

The previous prime is 20806243. The next prime is 20806271. The reversal of 20806259 is 95260802.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20806259 - 2⁴ = 20806243 is a prime.

It is a Chen prime.

It is equal to p_1318496 and since 20806259 and 1318496 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (20806459) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10403129 + 10403130.

It is an arithmetic number, because the mean of its divisors is an integer number (10403130).

Almost surely, 2^20806259 is an apocalyptic number.

20806259 is a deficient number, since it is larger than the sum of its proper divisors (1).

20806259 is an equidigital number, since it uses as much as digits as its factorization.

20806259 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8640, while the sum is 32.

The square root of 20806259 is about 4561.3878370514. The cubic root of 20806259 is about 275.0413557639.

The spelling of 20806259 in words is "twenty million, eight hundred six thousand, two hundred fifty-nine".