649941778920 has 256 divisors, whose sum is σ = 2336796864000. Its totient is φ = 141470171136.

The previous prime is 649941778919. The next prime is 649941778957. The reversal of 649941778920 is 29877149946.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1595536 + ... + 1961024.

It is an arithmetic number, because the mean of its divisors is an integer number (9128112750).

Almost surely, 2^649941778920 is an apocalyptic number.

649941778920 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 649941778920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1168398432000).

649941778920 is an abundant number, since it is smaller than the sum of its proper divisors (1686855085080).

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

649941778920 is a wasteful number, since it uses less digits than its factorization.

649941778920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 365612 (or 365608 counting only the distinct ones).

The product of its (nonzero) digits is 54867456, while the sum is 66.

The spelling of 649941778920 in words is "six hundred forty-nine billion, nine hundred forty-one million, seven hundred seventy-eight thousand, nine hundred twenty".