64991336256 has 560 divisors, whose sum is σ = 250671421440. Its totient is φ = 16144634880.

The previous prime is 64991336251. The next prime is 64991336257. The reversal of 64991336256 is 65263319946.

64991336256 is a `hidden beast` number, since 6 + 4 + 9 + 9 + 1 + 3 + 3 + 625 + 6 = 666.

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 (64991336251) by changing a digit.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 9177325 + ... + 9184403.

Almost surely, 2^64991336256 is an apocalyptic number.

64991336256 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 64991336256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (125335710720).

64991336256 is an abundant number, since it is smaller than the sum of its proper divisors (185680085184).

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

64991336256 is a wasteful number, since it uses less digits than its factorization.

64991336256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7144 (or 7125 counting only the distinct ones).

The product of its digits is 6298560, while the sum is 54.

The spelling of 64991336256 in words is "sixty-four billion, nine hundred ninety-one million, three hundred thirty-six thousand, two hundred fifty-six".