20487109 has 2 divisors, whose sum is σ = 20487110. Its totient is φ = 20487108.

The previous prime is 20487107. The next prime is 20487113. The reversal of 20487109 is 90178402.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19228225 + 1258884 = 4385^2 + 1122^2 .

It is a cyclic number.

It is not a de Polignac number, because 20487109 - 2¹ = 20487107 is a prime.

Together with 20487107, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20487107) 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, 10243554 + 10243555.

It is an arithmetic number, because the mean of its divisors is an integer number (10243555).

Almost surely, 2^20487109 is an apocalyptic number.

It is an amenable number.

20487109 is a deficient number, since it is larger than the sum of its proper divisors (1).

20487109 is an equidigital number, since it uses as much as digits as its factorization.

20487109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4032, while the sum is 31.

The square root of 20487109 is about 4526.2687723996. The cubic root of 20487109 is about 273.6278046264.

The spelling of 20487109 in words is "twenty million, four hundred eighty-seven thousand, one hundred nine".