20916559 has 2 divisors, whose sum is σ = 20916560. Its totient is φ = 20916558.

The previous prime is 20916557. The next prime is 20916589. The reversal of 20916559 is 95561902.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20916559 - 2¹ = 20916557 is a prime.

It is a super-3 number, since 3×20916559³ (a number of 23 digits) contains 333 as substring.

Together with 20916557, 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 (20916557) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10458279 + 10458280.

It is an arithmetic number, because the mean of its divisors is an integer number (10458280).

Almost surely, 2^20916559 is an apocalyptic number.

20916559 is a deficient number, since it is larger than the sum of its proper divisors (1).

20916559 is an equidigital number, since it uses as much as digits as its factorization.

20916559 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 24300, while the sum is 37.

The square root of 20916559 is about 4573.4624738812. The cubic root of 20916559 is about 275.5265240388.

The spelling of 20916559 in words is "twenty million, nine hundred sixteen thousand, five hundred fifty-nine".