20407745 has 4 divisors (see below), whose sum is σ = 24489300. Its totient is φ = 16326192.

The previous prime is 20407727. The next prime is 20407747. The reversal of 20407745 is 54770402.

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 5166529 + 15241216 = 2273^2 + 3904^2 .

It is a cyclic number.

It is not a de Polignac number, because 20407745 - 2¹⁴ = 20391361 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20407747) 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 3 ways as a sum of consecutive naturals, for example, 2040770 + ... + 2040779.

It is an arithmetic number, because the mean of its divisors is an integer number (6122325).

Almost surely, 2^20407745 is an apocalyptic number.

It is an amenable number.

20407745 is a deficient number, since it is larger than the sum of its proper divisors (4081555).

20407745 is an equidigital number, since it uses as much as digits as its factorization.

20407745 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4081554.

The product of its (nonzero) digits is 7840, while the sum is 29.

The square root of 20407745 is about 4517.4932208029. The cubic root of 20407745 is about 273.2740163107.

The spelling of 20407745 in words is "twenty million, four hundred seven thousand, seven hundred forty-five".