20559679 has 16 divisors (see below), whose sum is σ = 24329728. Its totient is φ = 17006112.

The previous prime is 20559673. The next prime is 20559701. The reversal of 20559679 is 97695502.

It is a happy number.

It is a 12-Lehmer number, since φ(20559679) divides (20559679-1)¹².

It is a cyclic number.

It is not a de Polignac number, because 20559679 - 2⁷ = 20559551 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20559673) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 41974 + ... + 42460.

It is an arithmetic number, because the mean of its divisors is an integer number (1520608).

Almost surely, 2^20559679 is an apocalyptic number.

20559679 is a deficient number, since it is larger than the sum of its proper divisors (3770049).

20559679 is a wasteful number, since it uses less digits than its factorization.

20559679 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 694.

The product of its (nonzero) digits is 170100, while the sum is 43.

The square root of 20559679 is about 4534.2782226061. The cubic root of 20559679 is about 273.9505078705.

The spelling of 20559679 in words is "twenty million, five hundred fifty-nine thousand, six hundred seventy-nine".