20478859 has 4 divisors (see below), whose sum is σ = 20814640. Its totient is φ = 20143080.

The previous prime is 20478823. The next prime is 20478869. The reversal of 20478859 is 95887402.

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 20478859 - 2¹¹ = 20476811 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20478869) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 167799 + ... + 167920.

It is an arithmetic number, because the mean of its divisors is an integer number (5203660).

Almost surely, 2^20478859 is an apocalyptic number.

20478859 is a deficient number, since it is larger than the sum of its proper divisors (335781).

20478859 is an equidigital number, since it uses as much as digits as its factorization.

20478859 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 335780.

The product of its (nonzero) digits is 161280, while the sum is 43.

The square root of 20478859 is about 4525.3573339572. The cubic root of 20478859 is about 273.5910704298.

The spelling of 20478859 in words is "twenty million, four hundred seventy-eight thousand, eight hundred fifty-nine".