20641864560 has 40 divisors (see below), whose sum is σ = 63989780880. Its totient is φ = 5504497152.

The previous prime is 20641864543. The next prime is 20641864571. The reversal of 20641864560 is 6546814602.

It is a tau number, because it is divible by the number of its divisors (40).

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 7 ways as a sum of consecutive naturals, for example, 43003645 + ... + 43004124.

It is an arithmetic number, because the mean of its divisors is an integer number (1599744522).

Almost surely, 2^20641864560 is an apocalyptic number.

20641864560 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20641864560 is an abundant number, since it is smaller than the sum of its proper divisors (43347916320).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20641864560 is a wasteful number, since it uses less digits than its factorization.

20641864560 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86007785 (or 86007779 counting only the distinct ones).

The product of its (nonzero) digits is 276480, while the sum is 42.

The spelling of 20641864560 in words is "twenty billion, six hundred forty-one million, eight hundred sixty-four thousand, five hundred sixty".