20866291 has 2 divisors, whose sum is σ = 20866292. Its totient is φ = 20866290.

The previous prime is 20866289. The next prime is 20866303. The reversal of 20866291 is 19266802.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20866291 - 2¹ = 20866289 is a prime.

Together with 20866289, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (20866201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10433145 + 10433146.

It is an arithmetic number, because the mean of its divisors is an integer number (10433146).

Almost surely, 2^20866291 is an apocalyptic number.

20866291 is a deficient number, since it is larger than the sum of its proper divisors (1).

20866291 is an equidigital number, since it uses as much as digits as its factorization.

20866291 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 20866291 is about 4567.9635506427. The cubic root of 20866291 is about 275.3056260515.

The spelling of 20866291 in words is "twenty million, eight hundred sixty-six thousand, two hundred ninety-one".