64665877856646 has 128 divisors (see below), whose sum is σ = 153434155682304. Its totient is φ = 17943626373120.

The previous prime is 64665877856641. The next prime is 64665877856677.

64665877856646 is nontrivially palindromic in base 10.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64665877856641) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1241948305 + ... + 1242000371.

It is an arithmetic number, because the mean of its divisors is an integer number (1198704341268).

Almost surely, 2^{64665877856646} is an apocalyptic number.

64665877856646 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 64665877856646, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (76717077841152).

64665877856646 is an abundant number, since it is smaller than the sum of its proper divisors (88768277825658).

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

64665877856646 is a wasteful number, since it uses less digits than its factorization.

64665877856646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82054.

The product of its digits is 58525286400, while the sum is 84.

The spelling of 64665877856646 in words is "sixty-four trillion, six hundred sixty-five billion, eight hundred seventy-seven million, eight hundred fifty-six thousand, six hundred forty-six".