20461509 has 6 divisors (see below), whose sum is σ = 29555526. Its totient is φ = 13641000.

The previous prime is 20461487. The next prime is 20461517. The reversal of 20461509 is 90516402.

It can be written as a sum of positive squares in only one way, i.e., 18948609 + 1512900 = 4353^2 + 1230^2 .

It is not a de Polignac number, because 20461509 - 2⁸ = 20461253 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20461579) 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 5 ways as a sum of consecutive naturals, for example, 1136742 + ... + 1136759.

It is an arithmetic number, because the mean of its divisors is an integer number (4925921).

Almost surely, 2^20461509 is an apocalyptic number.

It is an amenable number.

20461509 is a deficient number, since it is larger than the sum of its proper divisors (9094017).

20461509 is a wasteful number, since it uses less digits than its factorization.

20461509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2273507 (or 2273504 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 20461509 is about 4523.4399520719. The cubic root of 20461509 is about 273.5137850982.

The spelling of 20461509 in words is "twenty million, four hundred sixty-one thousand, five hundred nine".