20858261 has 2 divisors, whose sum is σ = 20858262. Its totient is φ = 20858260.

The previous prime is 20858251. The next prime is 20858273. The reversal of 20858261 is 16285802.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15952036 + 4906225 = 3994^2 + 2215^2 .

It is a cyclic number.

It is not a de Polignac number, because 20858261 - 2⁶ = 20858197 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20858231) 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, 10429130 + 10429131.

It is an arithmetic number, because the mean of its divisors is an integer number (10429131).

Almost surely, 2^20858261 is an apocalyptic number.

It is an amenable number.

20858261 is a deficient number, since it is larger than the sum of its proper divisors (1).

20858261 is an equidigital number, since it uses as much as digits as its factorization.

20858261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7680, while the sum is 32.

The square root of 20858261 is about 4567.0845185961. The cubic root of 20858261 is about 275.2703061214.

The spelling of 20858261 in words is "twenty million, eight hundred fifty-eight thousand, two hundred sixty-one".