20120509 has 2 divisors, whose sum is σ = 20120510. Its totient is φ = 20120508.

The previous prime is 20120501. The next prime is 20120531. The reversal of 20120509 is 90502102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17825284 + 2295225 = 4222^2 + 1515^2 .

It is a cyclic number.

It is not a de Polignac number, because 20120509 - 2³ = 20120501 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20120501) 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 as a sum of consecutive naturals, namely, 10060254 + 10060255.

It is an arithmetic number, because the mean of its divisors is an integer number (10060255).

Almost surely, 2^20120509 is an apocalyptic number.

It is an amenable number.

20120509 is a deficient number, since it is larger than the sum of its proper divisors (1).

20120509 is an equidigital number, since it uses as much as digits as its factorization.

20120509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 180, while the sum is 19.

The square root of 20120509 is about 4485.5890360130. The cubic root of 20120509 is about 271.9858565671.

The spelling of 20120509 in words is "twenty million, one hundred twenty thousand, five hundred nine".