20557841 has 4 divisors (see below), whose sum is σ = 20580900. Its totient is φ = 20534784.

The previous prime is 20557819. The next prime is 20557853. The reversal of 20557841 is 14875502.

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 9634816 + 10923025 = 3104^2 + 3305^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20557841 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20557798 and 20557807.

It is not an unprimeable number, because it can be changed into a prime (20557861) 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, 10136 + ... + 11993.

It is an arithmetic number, because the mean of its divisors is an integer number (5145225).

Almost surely, 2^20557841 is an apocalyptic number.

It is an amenable number.

20557841 is a deficient number, since it is larger than the sum of its proper divisors (23059).

20557841 is an equidigital number, since it uses as much as digits as its factorization.

20557841 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 23058.

The product of its (nonzero) digits is 11200, while the sum is 32.

The square root of 20557841 is about 4534.0755397324. The cubic root of 20557841 is about 273.9423440589.

The spelling of 20557841 in words is "twenty million, five hundred fifty-seven thousand, eight hundred forty-one".