64891936512 has 576 divisors, whose sum is σ = 228451829760. Its totient is φ = 17965449216.

The previous prime is 64891936511. The next prime is 64891936517. The reversal of 64891936512 is 21563919846.

64891936512 is a `hidden beast` number, since 6 + 4 + 8 + 91 + 9 + 36 + 512 = 666.

It is a tau number, because it is divible by the number of its divisors (576).

It is a super-2 number, since 2×64891936512² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64891936511) 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 63 ways as a sum of consecutive naturals, for example, 35132773 + ... + 35134619.

It is an arithmetic number, because the mean of its divisors is an integer number (396617760).

Almost surely, 2^64891936512 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 64891936512, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (114225914880).

64891936512 is an abundant number, since it is smaller than the sum of its proper divisors (163559893248).

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

64891936512 is a wasteful number, since it uses less digits than its factorization.

64891936512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1925 (or 1905 counting only the distinct ones).

The product of its digits is 2799360, while the sum is 54.

The spelling of 64891936512 in words is "sixty-four billion, eight hundred ninety-one million, nine hundred thirty-six thousand, five hundred twelve".