64721386512 has 60 divisors (see below), whose sum is σ = 181643250204. Its totient is φ = 21512663040.

The previous prime is 64721386493. The next prime is 64721386517. The reversal of 64721386512 is 21568312746.

64721386512 is a `hidden beast` number, since 6 + 47 + 2 + 13 + 86 + 512 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 24141701376 + 40579685136 = 155376^2 + 201444^2 .

It is a super-2 number, since 2×64721386512² (a number of 22 digits) contains 22 as substring.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (64721386517) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 585789 + ... + 687452.

Almost surely, 2^64721386512 is an apocalyptic number.

It is an amenable number.

64721386512 is an abundant number, since it is smaller than the sum of its proper divisors (116921863692).

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

64721386512 is a wasteful number, since it uses less digits than its factorization.

64721386512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1273608 (or 1273599 counting only the distinct ones).

The product of its digits is 483840, while the sum is 45.

The spelling of 64721386512 in words is "sixty-four billion, seven hundred twenty-one million, three hundred eighty-six thousand, five hundred twelve".