20905279 has 2 divisors, whose sum is σ = 20905280. Its totient is φ = 20905278.

The previous prime is 20905277. The next prime is 20905303. The reversal of 20905279 is 97250902.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20905279 - 2¹ = 20905277 is a prime.

Together with 20905277, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20905277) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10452639 + 10452640.

It is an arithmetic number, because the mean of its divisors is an integer number (10452640).

Almost surely, 2^20905279 is an apocalyptic number.

20905279 is a deficient number, since it is larger than the sum of its proper divisors (1).

20905279 is an equidigital number, since it uses as much as digits as its factorization.

20905279 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11340, while the sum is 34.

The square root of 20905279 is about 4572.2291062457. The cubic root of 20905279 is about 275.4769859663.

The spelling of 20905279 in words is "twenty million, nine hundred five thousand, two hundred seventy-nine".