64397720020 has 24 divisors (see below), whose sum is σ = 137527336800. Its totient is φ = 25322492832.

The previous prime is 64397719993. The next prime is 64397720029. The reversal of 64397720020 is 2002779346.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64397720029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 27285990 + ... + 27288349.

It is an arithmetic number, because the mean of its divisors is an integer number (5730305700).

Almost surely, 2^64397720020 is an apocalyptic number.

It is an amenable number.

64397720020 is an abundant number, since it is smaller than the sum of its proper divisors (73129616780).

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

64397720020 is a wasteful number, since it uses less digits than its factorization.

64397720020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54574407 (or 54574405 counting only the distinct ones).

The product of its (nonzero) digits is 127008, while the sum is 40.

The spelling of 64397720020 in words is "sixty-four billion, three hundred ninety-seven million, seven hundred twenty thousand, twenty".