20556205 has 4 divisors (see below), whose sum is σ = 24667452. Its totient is φ = 16444960.

The previous prime is 20556199. The next prime is 20556223. The reversal of 20556205 is 50265502.

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

It can be written as a sum of positive squares in 2 ways, for example, as 6702921 + 13853284 = 2589^2 + 3722^2 .

It is not a de Polignac number, because 20556205 - 2¹³ = 20548013 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20556205.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2055616 + ... + 2055625.

It is an arithmetic number, because the mean of its divisors is an integer number (6166863).

Almost surely, 2^20556205 is an apocalyptic number.

It is an amenable number.

20556205 is a deficient number, since it is larger than the sum of its proper divisors (4111247).

20556205 is an equidigital number, since it uses as much as digits as its factorization.

20556205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4111246.

The product of its (nonzero) digits is 3000, while the sum is 25.

The square root of 20556205 is about 4533.8951245039. The cubic root of 20556205 is about 273.9350770577.

The spelling of 20556205 in words is "twenty million, five hundred fifty-six thousand, two hundred five".