20505385 has 8 divisors (see below), whose sum is σ = 24643080. Its totient is φ = 16379904.

The previous prime is 20505379. The next prime is 20505409. The reversal of 20505385 is 58350502.

It can be written as a sum of positive squares in 4 ways, for example, as 7160976 + 13344409 = 2676^2 + 3653^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20505385 - 2⁷ = 20505257 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1179 + ... + 6511.

It is an arithmetic number, because the mean of its divisors is an integer number (3080385).

Almost surely, 2^20505385 is an apocalyptic number.

It is an amenable number.

20505385 is a deficient number, since it is larger than the sum of its proper divisors (4137695).

20505385 is an equidigital number, since it uses as much as digits as its factorization.

20505385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6107.

The product of its (nonzero) digits is 6000, while the sum is 28.

The square root of 20505385 is about 4528.2872037891. The cubic root of 20505385 is about 273.7091457836.

Adding to 20505385 its reverse (58350502), we get a palindrome (78855887).

The spelling of 20505385 in words is "twenty million, five hundred five thousand, three hundred eighty-five".