20439145 has 4 divisors (see below), whose sum is σ = 24526980. Its totient is φ = 16351312.

The previous prime is 20439143. The next prime is 20439149. The reversal of 20439145 is 54193402.

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 3988009 + 16451136 = 1997^2 + 4056^2 .

It is a cyclic number.

It is not a de Polignac number, because 20439145 - 2¹ = 20439143 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20439143) 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, 2043910 + ... + 2043919.

It is an arithmetic number, because the mean of its divisors is an integer number (6131745).

Almost surely, 2^20439145 is an apocalyptic number.

It is an amenable number.

20439145 is a deficient number, since it is larger than the sum of its proper divisors (4087835).

20439145 is an equidigital number, since it uses as much as digits as its factorization.

20439145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4087834.

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 20439145 is about 4520.9672637612. The cubic root of 20439145 is about 273.4141004956.

The spelling of 20439145 in words is "twenty million, four hundred thirty-nine thousand, one hundred forty-five".