20646864603 has 24 divisors (see below), whose sum is σ = 31117614528. Its totient is φ = 13680104904.

The previous prime is 20646864587. The next prime is 20646864607. The reversal of 20646864603 is 30646864602.

It is not a de Polignac number, because 20646864603 - 2⁴ = 20646864587 is a prime.

It is a super-2 number, since 2×20646864603² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (20646864607) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 221025 + ... + 300242.

It is an arithmetic number, because the mean of its divisors is an integer number (1296567272).

Almost surely, 2^20646864603 is an apocalyptic number.

20646864603 is a deficient number, since it is larger than the sum of its proper divisors (10470749925).

20646864603 is an equidigital number, since it uses as much as digits as its factorization.

20646864603 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 521445 (or 521433 counting only the distinct ones).

The product of its (nonzero) digits is 995328, while the sum is 45.

Subtracting 20646864603 from its reverse (30646864602), we obtain a palindrome (9999999999).

The spelling of 20646864603 in words is "twenty billion, six hundred forty-six million, eight hundred sixty-four thousand, six hundred three".