20478559 has 2 divisors, whose sum is σ = 20478560. Its totient is φ = 20478558.

The previous prime is 20478551. The next prime is 20478571. The reversal of 20478559 is 95587402.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20478559 - 2³ = 20478551 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20478551) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10239279 + 10239280.

It is an arithmetic number, because the mean of its divisors is an integer number (10239280).

Almost surely, 2^20478559 is an apocalyptic number.

20478559 is a deficient number, since it is larger than the sum of its proper divisors (1).

20478559 is an equidigital number, since it uses as much as digits as its factorization.

20478559 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 100800, while the sum is 40.

The square root of 20478559 is about 4525.3241872821. The cubic root of 20478559 is about 273.5897344549.

The spelling of 20478559 in words is "twenty million, four hundred seventy-eight thousand, five hundred fifty-nine".