20506775 has 6 divisors (see below), whose sum is σ = 25428432. Its totient is φ = 16405400.

The previous prime is 20506771. The next prime is 20506781. The reversal of 20506775 is 57760502.

It is a happy number.

It is not a de Polignac number, because 20506775 - 2² = 20506771 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20506771) 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 in 5 ways as a sum of consecutive naturals, for example, 410111 + ... + 410160.

It is an arithmetic number, because the mean of its divisors is an integer number (4238072).

Almost surely, 2^20506775 is an apocalyptic number.

20506775 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

20506775 is a deficient number, since it is larger than the sum of its proper divisors (4921657).

20506775 is an equidigital number, since it uses as much as digits as its factorization.

20506775 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 820281 (or 820276 counting only the distinct ones).

The product of its (nonzero) digits is 14700, while the sum is 32.

The square root of 20506775 is about 4528.4406808525. The cubic root of 20506775 is about 273.7153302910.

The spelling of 20506775 in words is "twenty million, five hundred six thousand, seven hundred seventy-five".