20559491 has 4 divisors (see below), whose sum is σ = 21060984. Its totient is φ = 20058000.

The previous prime is 20559449. The next prime is 20559503. The reversal of 20559491 is 19495502.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20559491 - 2²² = 16365187 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20559421) 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 3 ways as a sum of consecutive naturals, for example, 250685 + ... + 250766.

It is an arithmetic number, because the mean of its divisors is an integer number (5265246).

Almost surely, 2^20559491 is an apocalyptic number.

20559491 is a deficient number, since it is larger than the sum of its proper divisors (501493).

20559491 is an equidigital number, since it uses as much as digits as its factorization.

20559491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 501492.

The product of its (nonzero) digits is 16200, while the sum is 35.

The square root of 20559491 is about 4534.2574915856. The cubic root of 20559491 is about 273.9496728566.

The spelling of 20559491 in words is "twenty million, five hundred fifty-nine thousand, four hundred ninety-one".