20943745 has 16 divisors (see below), whose sum is σ = 27118800. Its totient is φ = 15468544.

The previous prime is 20943737. The next prime is 20943749. The reversal of 20943745 is 54734902.

It can be written as a sum of positive squares in 8 ways, for example, as 4999696 + 15944049 = 2236^2 + 3993^2 .

It is a cyclic number.

It is not a de Polignac number, because 20943745 - 2³ = 20943737 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20943745.

It is not an unprimeable number, because it can be changed into a prime (20943749) by changing a digit.

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, 2181 + ... + 6829.

It is an arithmetic number, because the mean of its divisors is an integer number (1694925).

Almost surely, 2^20943745 is an apocalyptic number.

It is an amenable number.

20943745 is a deficient number, since it is larger than the sum of its proper divisors (6175055).

20943745 is a wasteful number, since it uses less digits than its factorization.

20943745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4724.

The product of its (nonzero) digits is 30240, while the sum is 34.

The square root of 20943745 is about 4576.4336551511. The cubic root of 20943745 is about 275.6458429193.

The spelling of 20943745 in words is "twenty million, nine hundred forty-three thousand, seven hundred forty-five".