20685975 has 12 divisors (see below), whose sum is σ = 34200936. Its totient is φ = 11032480.

The previous prime is 20685971. The next prime is 20685983. The reversal of 20685975 is 57958602.

It is not a de Polignac number, because 20685975 - 2² = 20685971 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20685971) 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, 137832 + ... + 137981.

It is an arithmetic number, because the mean of its divisors is an integer number (2850078).

Almost surely, 2^20685975 is an apocalyptic number.

20685975 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

20685975 is a deficient number, since it is larger than the sum of its proper divisors (13514961).

20685975 is a wasteful number, since it uses less digits than its factorization.

20685975 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 275826 (or 275821 counting only the distinct ones).

The product of its (nonzero) digits is 151200, while the sum is 42.

The square root of 20685975 is about 4548.1837034139. The cubic root of 20685975 is about 274.5103131151.

It can be divided in two parts, 2068597 and 5, that added together give a palindrome (2068602).

The spelling of 20685975 in words is "twenty million, six hundred eighty-five thousand, nine hundred seventy-five".