20505475 has 12 divisors (see below), whose sum is σ = 25616664. Its totient is φ = 16281920.

The previous prime is 20505473. The next prime is 20505487. The reversal of 20505475 is 57450502.

It is not a de Polignac number, because 20505475 - 2¹ = 20505473 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20505473) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 432 + ... + 6418.

It is an arithmetic number, because the mean of its divisors is an integer number (2134722).

Almost surely, 2^20505475 is an apocalyptic number.

20505475 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

20505475 is a deficient number, since it is larger than the sum of its proper divisors (5111189).

20505475 is a wasteful number, since it uses less digits than its factorization.

20505475 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6134 (or 6129 counting only the distinct ones).

The product of its (nonzero) digits is 7000, while the sum is 28.

The square root of 20505475 is about 4528.2971413104. The cubic root of 20505475 is about 273.7095462278.

Adding to 20505475 its reverse (57450502), we get a palindrome (77955977).

The spelling of 20505475 in words is "twenty million, five hundred five thousand, four hundred seventy-five".