20808479 has 2 divisors, whose sum is σ = 20808480. Its totient is φ = 20808478.

The previous prime is 20808461. The next prime is 20808481. The reversal of 20808479 is 97480802.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20808479 - 2²⁰ = 19759903 is a prime.

Together with 20808481, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20808419) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10404239 + 10404240.

It is an arithmetic number, because the mean of its divisors is an integer number (10404240).

Almost surely, 2^20808479 is an apocalyptic number.

20808479 is a deficient number, since it is larger than the sum of its proper divisors (1).

20808479 is an equidigital number, since it uses as much as digits as its factorization.

20808479 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32256, while the sum is 38.

The square root of 20808479 is about 4561.6311775504. The cubic root of 20808479 is about 275.0511375976.

The spelling of 20808479 in words is "twenty million, eight hundred eight thousand, four hundred seventy-nine".