646778160 has 240 divisors, whose sum is σ = 2499631680. Its totient is φ = 146810880.

The previous prime is 646778159. The next prime is 646778189. The reversal of 646778160 is 61877646.

It is a tau number, because it is divible by the number of its divisors (240).

It is a Harshad number since it is a multiple of its sum of digits (45).

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, 911886 + ... + 912594.

It is an arithmetic number, because the mean of its divisors is an integer number (10415132).

Almost surely, 2^646778160 is an apocalyptic number.

646778160 is a gapful number since it is divisible by the number (60) 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 646778160, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1249815840).

646778160 is an abundant number, since it is smaller than the sum of its proper divisors (1852853520).

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

646778160 is a wasteful number, since it uses less digits than its factorization.

646778160 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 916 (or 907 counting only the distinct ones).

The product of its (nonzero) digits is 338688, while the sum is 45.

The square root of 646778160 is about 25431.8335949259. The cubic root of 646778160 is about 864.8055116441.

The spelling of 646778160 in words is "six hundred forty-six million, seven hundred seventy-eight thousand, one hundred sixty".