649784720 has 80 divisors (see below), whose sum is σ = 1637030640. Its totient is φ = 239855616.

The previous prime is 649784719. The next prime is 649784731. The reversal of 649784720 is 27487946.

649784720 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 8 ways, for example, as 600054016 + 49730704 = 24496^2 + 7052^2 .

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 173912 + ... + 177608.

It is an arithmetic number, because the mean of its divisors is an integer number (20462883).

Almost surely, 2^649784720 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 649784720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (818515320).

649784720 is an abundant number, since it is smaller than the sum of its proper divisors (987245920).

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

649784720 is a wasteful number, since it uses less digits than its factorization.

649784720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3749 (or 3717 counting only the distinct ones).

The product of its (nonzero) digits is 677376, while the sum is 47.

The square root of 649784720 is about 25490.8752301681. The cubic root of 649784720 is about 866.1434619839.

The spelling of 649784720 in words is "six hundred forty-nine million, seven hundred eighty-four thousand, seven hundred twenty".