20889551 has 2 divisors, whose sum is σ = 20889552. Its totient is φ = 20889550.

The previous prime is 20889521. The next prime is 20889553. The reversal of 20889551 is 15598802.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20889551 - 2⁶ = 20889487 is a prime.

Together with 20889553, 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 (20889553) 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, 10444775 + 10444776.

It is an arithmetic number, because the mean of its divisors is an integer number (10444776).

Almost surely, 2^20889551 is an apocalyptic number.

20889551 is a deficient number, since it is larger than the sum of its proper divisors (1).

20889551 is an equidigital number, since it uses as much as digits as its factorization.

20889551 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 28800, while the sum is 38.

The square root of 20889551 is about 4570.5088338171. The cubic root of 20889551 is about 275.4078839777.

The spelling of 20889551 in words is "twenty million, eight hundred eighty-nine thousand, five hundred fifty-one".