20855213 has 2 divisors, whose sum is σ = 20855214. Its totient is φ = 20855212.

The previous prime is 20855207. The next prime is 20855221. The reversal of 20855213 is 31255802.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16024009 + 4831204 = 4003^2 + 2198^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20855213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20851213) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10427606 + 10427607.

It is an arithmetic number, because the mean of its divisors is an integer number (10427607).

Almost surely, 2^20855213 is an apocalyptic number.

It is an amenable number.

20855213 is a deficient number, since it is larger than the sum of its proper divisors (1).

20855213 is an equidigital number, since it uses as much as digits as its factorization.

20855213 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2400, while the sum is 26.

The square root of 20855213 is about 4566.7508143099. The cubic root of 20855213 is about 275.2568971294.

The spelling of 20855213 in words is "twenty million, eight hundred fifty-five thousand, two hundred thirteen".