20986559 has 8 divisors (see below), whose sum is σ = 23117952. Its totient is φ = 18892440.

The previous prime is 20986531. The next prime is 20986561. The reversal of 20986559 is 95568902.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20986559 - 2¹⁶ = 20921023 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20986519) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8129 + ... + 10394.

It is an arithmetic number, because the mean of its divisors is an integer number (2889744).

Almost surely, 2^20986559 is an apocalyptic number.

20986559 is a deficient number, since it is larger than the sum of its proper divisors (2131393).

20986559 is a wasteful number, since it uses less digits than its factorization.

20986559 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18637.

The product of its (nonzero) digits is 194400, while the sum is 44.

The square root of 20986559 is about 4581.1089268866. The cubic root of 20986559 is about 275.8335436473.

It can be divided in two parts, 209 and 86559, that added together give a palindrome (86768).

The spelling of 20986559 in words is "twenty million, nine hundred eighty-six thousand, five hundred fifty-nine".