20645641064 has 16 divisors (see below), whose sum is σ = 40393645920. Its totient is φ = 9874002160.

The previous prime is 20645641057. The next prime is 20645641069. The reversal of 20645641064 is 46014654602.

It is not an unprimeable number, because it can be changed into a prime (20645641069) 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 3 ways as a sum of consecutive naturals, for example, 56102102 + ... + 56102469.

It is an arithmetic number, because the mean of its divisors is an integer number (2524602870).

Almost surely, 2^20645641064 is an apocalyptic number.

It is an amenable number.

20645641064 is a deficient number, since it is larger than the sum of its proper divisors (19748004856).

20645641064 is a wasteful number, since it uses less digits than its factorization.

20645641064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 112204600 (or 112204596 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 38.

The spelling of 20645641064 in words is "twenty billion, six hundred forty-five million, six hundred forty-one thousand, sixty-four".