64910921856 has 256 divisors, whose sum is σ = 195432652800. Its totient is φ = 18916352000.

The previous prime is 64910921827. The next prime is 64910921861. The reversal of 64910921856 is 65812901946.

It is a junction number, because it is equal to n+sod(n) for n = 64910921799 and 64910921808.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 12293425 + ... + 12298703.

It is an arithmetic number, because the mean of its divisors is an integer number (763408800).

Almost surely, 2^64910921856 is an apocalyptic number.

64910921856 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 64910921856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (97716326400).

64910921856 is an abundant number, since it is smaller than the sum of its proper divisors (130521730944).

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

64910921856 is a wasteful number, since it uses less digits than its factorization.

64910921856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5419 (or 5407 counting only the distinct ones).

The product of its (nonzero) digits is 933120, while the sum is 51.

The spelling of 64910921856 in words is "sixty-four billion, nine hundred ten million, nine hundred twenty-one thousand, eight hundred fifty-six".