20645641063 has 4 divisors (see below), whose sum is σ = 21203631400. Its totient is φ = 20087650728.

The previous prime is 20645641057. The next prime is 20645641069. The reversal of 20645641063 is 36014654602.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 36014654602 = 2 ⋅18007327301.

It is an interprime number because it is at equal distance from previous prime (20645641057) and next prime (20645641069).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20645641063 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (37), and also a Moran number because the ratio is a prime number: 557990299 = 20645641063 / (2 + 0 + 6 + 4 + 5 + 6 + 4 + 1 + 0 + 6 + 3).

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20645641069) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 278995113 + ... + 278995186.

It is an arithmetic number, because the mean of its divisors is an integer number (5300907850).

Almost surely, 2^20645641063 is an apocalyptic number.

20645641063 is a deficient number, since it is larger than the sum of its proper divisors (557990337).

20645641063 is an equidigital number, since it uses as much as digits as its factorization.

20645641063 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 557990336.

The product of its (nonzero) digits is 103680, while the sum is 37.

The spelling of 20645641063 in words is "twenty billion, six hundred forty-five million, six hundred forty-one thousand, sixty-three".