20389745 has 4 divisors (see below), whose sum is σ = 24467700. Its totient is φ = 16311792.

The previous prime is 20389741. The next prime is 20389763. The reversal of 20389745 is 54798302.

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 15689521 + 4700224 = 3961^2 + 2168^2 .

It is a cyclic number.

It is not a de Polignac number, because 20389745 - 2² = 20389741 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20389699 and 20389708.

It is not an unprimeable number, because it can be changed into a prime (20389741) 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, 2038970 + ... + 2038979.

It is an arithmetic number, because the mean of its divisors is an integer number (6116925).

Almost surely, 2^20389745 is an apocalyptic number.

It is an amenable number.

20389745 is a deficient number, since it is larger than the sum of its proper divisors (4077955).

20389745 is an equidigital number, since it uses as much as digits as its factorization.

20389745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4077954.

The product of its (nonzero) digits is 60480, while the sum is 38.

The square root of 20389745 is about 4515.5005259661. The cubic root of 20389745 is about 273.1936484700.

It can be divided in two parts, 2038974 and 5, that multiplied together give a triangular number (10194870 = T₄₅₁₅).

The spelling of 20389745 in words is "twenty million, three hundred eighty-nine thousand, seven hundred forty-five".