20666825 has 6 divisors (see below), whose sum is σ = 25626894. Its totient is φ = 16533440.

The previous prime is 20666791. The next prime is 20666827. The reversal of 20666825 is 52866602.

It can be written as a sum of positive squares in 3 ways, for example, as 6431296 + 14235529 = 2536^2 + 3773^2 .

It is a de Polignac number, because none of the positive numbers 2^k-20666825 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (20666827) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 413312 + ... + 413361.

It is an arithmetic number, because the mean of its divisors is an integer number (4271149).

Almost surely, 2^20666825 is an apocalyptic number.

20666825 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

20666825 is a deficient number, since it is larger than the sum of its proper divisors (4960069).

20666825 is an equidigital number, since it uses as much as digits as its factorization.

20666825 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 826683 (or 826678 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 35.

The square root of 20666825 is about 4546.0779799735. The cubic root of 20666825 is about 274.4255778374.

The spelling of 20666825 in words is "twenty million, six hundred sixty-six thousand, eight hundred twenty-five".