20492509 has 2 divisors, whose sum is σ = 20492510. Its totient is φ = 20492508.

The previous prime is 20492489. The next prime is 20492513. The reversal of 20492509 is 90529402.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18922500 + 1570009 = 4350^2 + 1253^2 .

It is a cyclic number.

It is not a de Polignac number, because 20492509 - 2⁵ = 20492477 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20492569) 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, 10246254 + 10246255.

It is an arithmetic number, because the mean of its divisors is an integer number (10246255).

Almost surely, 2^20492509 is an apocalyptic number.

It is an amenable number.

20492509 is a deficient number, since it is larger than the sum of its proper divisors (1).

20492509 is an equidigital number, since it uses as much as digits as its factorization.

20492509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 20492509 is about 4526.8652509214. The cubic root of 20492509 is about 273.6518434882.

The spelling of 20492509 in words is "twenty million, four hundred ninety-two thousand, five hundred nine".