20663643245 has 12 divisors (see below), whose sum is σ = 28844759484. Its totient is φ = 14169355200.

The previous prime is 20663643239. The next prime is 20663643251. The reversal of 20663643245 is 54234636602.

It is an interprime number because it is at equal distance from previous prime (20663643239) and next prime (20663643251).

It can be written as a sum of positive squares in 2 ways, for example, as 3707957449 + 16955685796 = 60893^2 + 130214^2 .

It is not a de Polignac number, because 20663643245 - 2²² = 20659448941 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 42170456 + ... + 42170945.

It is an arithmetic number, because the mean of its divisors is an integer number (2403729957).

Almost surely, 2^20663643245 is an apocalyptic number.

It is an amenable number.

20663643245 is a deficient number, since it is larger than the sum of its proper divisors (8181116239).

20663643245 is an equidigital number, since it uses as much as digits as its factorization.

20663643245 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84341420 (or 84341413 counting only the distinct ones).

The product of its (nonzero) digits is 622080, while the sum is 41.

The spelling of 20663643245 in words is "twenty billion, six hundred sixty-three million, six hundred forty-three thousand, two hundred forty-five".