647621908920 has 384 divisors, whose sum is σ = 2485905776640. Its totient is φ = 143087938560.

The previous prime is 647621908907. The next prime is 647621908931. The reversal of 647621908920 is 29809126746.

647621908920 is a `hidden beast` number, since 6 + 4 + 7 + 621 + 9 + 0 + 8 + 9 + 2 + 0 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 75537754 + ... + 75546326.

It is an arithmetic number, because the mean of its divisors is an integer number (6473712960).

Almost surely, 2^647621908920 is an apocalyptic number.

647621908920 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 647621908920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1242952888320).

647621908920 is an abundant number, since it is smaller than the sum of its proper divisors (1838283867720).

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

647621908920 is a wasteful number, since it uses less digits than its factorization.

647621908920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9595 (or 9588 counting only the distinct ones).

The product of its (nonzero) digits is 2612736, while the sum is 54.

The spelling of 647621908920 in words is "six hundred forty-seven billion, six hundred twenty-one million, nine hundred eight thousand, nine hundred twenty".