20408505 has 16 divisors (see below), whose sum is σ = 35165760. Its totient is φ = 10047168.

The previous prime is 20408471. The next prime is 20408533. The reversal of 20408505 is 50580402.

It is not a de Polignac number, because 20408505 - 2⁹ = 20407993 is a prime.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 52135 + ... + 52524.

It is an arithmetic number, because the mean of its divisors is an integer number (2197860).

Almost surely, 2^20408505 is an apocalyptic number.

It is an amenable number.

20408505 is a deficient number, since it is larger than the sum of its proper divisors (14757255).

20408505 is a wasteful number, since it uses less digits than its factorization.

20408505 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104680.

The product of its (nonzero) digits is 1600, while the sum is 24.

The square root of 20408505 is about 4517.5773374675. The cubic root of 20408505 is about 273.2774085796.

Adding to 20408505 its reverse (50580402), we get a palindrome (70988907).

The spelling of 20408505 in words is "twenty million, four hundred eight thousand, five hundred five".