20784745 has 16 divisors (see below), whose sum is σ = 26045712. Its totient is φ = 15907840.

The previous prime is 20784733. The next prime is 20784767. The reversal of 20784745 is 54748702.

It can be written as a sum of positive squares in 8 ways, for example, as 18496 + 20766249 = 136^2 + 4557^2 .

It is not a de Polignac number, because 20784745 - 2¹⁷ = 20653673 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9909 + ... + 11821.

It is an arithmetic number, because the mean of its divisors is an integer number (1627857).

Almost surely, 2^20784745 is an apocalyptic number.

It is an amenable number.

20784745 is a deficient number, since it is larger than the sum of its proper divisors (5260967).

20784745 is a wasteful number, since it uses less digits than its factorization.

20784745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2012.

The product of its (nonzero) digits is 62720, while the sum is 37.

The square root of 20784745 is about 4559.0289536260. The cubic root of 20784745 is about 274.9465240371.

The spelling of 20784745 in words is "twenty million, seven hundred eighty-four thousand, seven hundred forty-five".