20147009 has 4 divisors (see below), whose sum is σ = 20178516. Its totient is φ = 20115504.

The previous prime is 20146991. The next prime is 20147021. The reversal of 20147009 is 90074102.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90074102 = 2 ⋅45037051.

It can be written as a sum of positive squares in 2 ways, for example, as 3312400 + 16834609 = 1820^2 + 4103^2 .

It is a cyclic number.

It is not a de Polignac number, because 20147009 - 2²⁰ = 19098433 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20147059) 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, 14774 + ... + 16079.

It is an arithmetic number, because the mean of its divisors is an integer number (5044629).

Almost surely, 2^20147009 is an apocalyptic number.

It is an amenable number.

20147009 is a deficient number, since it is larger than the sum of its proper divisors (31507).

20147009 is an equidigital number, since it uses as much as digits as its factorization.

20147009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31506.

The product of its (nonzero) digits is 504, while the sum is 23.

The square root of 20147009 is about 4488.5419681674. The cubic root of 20147009 is about 272.1052117850.

The spelling of 20147009 in words is "twenty million, one hundred forty-seven thousand, nine".