20825393665 has 4 divisors (see below), whose sum is σ = 24990472404. Its totient is φ = 16660314928.

The previous prime is 20825393663. The next prime is 20825393681. The reversal of 20825393665 is 56639352802.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 4614756624 + 16210637041 = 67932^2 + 127321^2 .

It is a cyclic number.

It is not a de Polignac number, because 20825393665 - 2¹ = 20825393663 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20825393663) 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 3 ways as a sum of consecutive naturals, for example, 2082539362 + ... + 2082539371.

It is an arithmetic number, because the mean of its divisors is an integer number (6247618101).

Almost surely, 2^20825393665 is an apocalyptic number.

It is an amenable number.

20825393665 is a deficient number, since it is larger than the sum of its proper divisors (4165078739).

20825393665 is an equidigital number, since it uses as much as digits as its factorization.

20825393665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4165078738.

The product of its (nonzero) digits is 2332800, while the sum is 49.

The spelling of 20825393665 in words is "twenty billion, eight hundred twenty-five million, three hundred ninety-three thousand, six hundred sixty-five".