20508505 has 16 divisors (see below), whose sum is σ = 26337600. Its totient is φ = 15284160.

The previous prime is 20508503. The next prime is 20508517. The reversal of 20508505 is 50580502.

It is not a de Polignac number, because 20508505 - 2¹ = 20508503 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20508505.

It is not an unprimeable number, because it can be changed into a prime (20508503) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4026 + ... + 7564.

It is an arithmetic number, because the mean of its divisors is an integer number (1646100).

Almost surely, 2^20508505 is an apocalyptic number.

It is an amenable number.

20508505 is a deficient number, since it is larger than the sum of its proper divisors (5829095).

20508505 is a wasteful number, since it uses less digits than its factorization.

20508505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3624.

The product of its (nonzero) digits is 2000, while the sum is 25.

The square root of 20508505 is about 4528.6316918027. The cubic root of 20508505 is about 273.7230271653.

The spelling of 20508505 in words is "twenty million, five hundred eight thousand, five hundred five".