646677776646 has 96 divisors (see below), whose sum is σ = 1539444980736. Its totient is φ = 194565672000.

The previous prime is 646677776627. The next prime is 646677776663.

646677776646 is nontrivially palindromic in base 10.

646677776646 is digitally balanced in base 2 and base 4, because in such bases it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 17570155 + ... + 17606921.

It is an arithmetic number, because the mean of its divisors is an integer number (16035885216).

Almost surely, 2^646677776646 is an apocalyptic number.

646677776646 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 646677776646, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (769722490368).

646677776646 is an abundant number, since it is smaller than the sum of its proper divisors (892767204090).

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

646677776646 is a wasteful number, since it uses less digits than its factorization.

646677776646 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 37418 (or 37415 counting only the distinct ones).

The product of its digits is 1792336896, while the sum is 72.

The spelling of 646677776646 in words is "six hundred forty-six billion, six hundred seventy-seven million, seven hundred seventy-six thousand, six hundred forty-six".