20645818763 has 4 divisors (see below), whose sum is σ = 20646822120. Its totient is φ = 20644815408.

The previous prime is 20645818723. The next prime is 20645818799. The reversal of 20645818763 is 36781854602.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20645818763 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20645818723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 470153 + ... + 512186.

It is an arithmetic number, because the mean of its divisors is an integer number (5161705530).

Almost surely, 2^20645818763 is an apocalyptic number.

20645818763 is a deficient number, since it is larger than the sum of its proper divisors (1003357).

20645818763 is an equidigital number, since it uses as much as digits as its factorization.

20645818763 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1003356.

The product of its (nonzero) digits is 1935360, while the sum is 50.

The spelling of 20645818763 in words is "twenty billion, six hundred forty-five million, eight hundred eighteen thousand, seven hundred sixty-three".