648661680 has 120 divisors (see below), whose sum is σ = 2209278240. Its totient is φ = 170526720.

The previous prime is 648661661. The next prime is 648661681. The reversal of 648661680 is 86166846.

648661680 is a `hidden beast` number, since 6 + 486 + 6 + 168 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (120).

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

It is not an unprimeable number, because it can be changed into a prime (648661681) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 44776 + ... + 57464.

It is an arithmetic number, because the mean of its divisors is an integer number (18410652).

Almost surely, 2^648661680 is an apocalyptic number.

648661680 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 648661680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1104639120).

648661680 is an abundant number, since it is smaller than the sum of its proper divisors (1560616560).

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

648661680 is a wasteful number, since it uses less digits than its factorization.

648661680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12779 (or 12770 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 45.

The square root of 648661680 is about 25468.8374292978. The cubic root of 648661680 is about 865.6441814010.

The spelling of 648661680 in words is "six hundred forty-eight million, six hundred sixty-one thousand, six hundred eighty".