20543805 has 12 divisors (see below), whose sum is σ = 35609340. Its totient is φ = 10956672.

The previous prime is 20543801. The next prime is 20543827. The reversal of 20543805 is 50834502.

It can be written as a sum of positive squares in 2 ways, for example, as 14884164 + 5659641 = 3858^2 + 2379^2 .

It is not a de Polignac number, because 20543805 - 2² = 20543801 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20543801) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 228220 + ... + 228309.

It is an arithmetic number, because the mean of its divisors is an integer number (2967445).

Almost surely, 2^20543805 is an apocalyptic number.

It is an amenable number.

20543805 is a deficient number, since it is larger than the sum of its proper divisors (15065535).

20543805 is a wasteful number, since it uses less digits than its factorization.

20543805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 456540 (or 456537 counting only the distinct ones).

The product of its (nonzero) digits is 4800, while the sum is 27.

The square root of 20543805 is about 4532.5274406229. The cubic root of 20543805 is about 273.8799845573.

The spelling of 20543805 in words is "twenty million, five hundred forty-three thousand, eight hundred five".