647761121280 has 1560 divisors, whose sum is σ = 2913699833352. Its totient is φ = 136447524864.

The previous prime is 647761121269. The next prime is 647761121323. The reversal of 647761121280 is 82121167746.

647761121280 is a `hidden beast` number, since 6 + 4 + 7 + 7 + 611 + 2 + 1 + 28 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 35911766016 + 611849355264 = 189504^2 + 782208^2 .

It is a tau number, because it is divible by the number of its divisors (1560).

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 119 ways as a sum of consecutive naturals, for example, 1056706254 + ... + 1056706866.

Almost surely, 2^647761121280 is an apocalyptic number.

647761121280 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 647761121280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1456849916676).

647761121280 is an abundant number, since it is smaller than the sum of its proper divisors (2265938712072).

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

647761121280 is a wasteful number, since it uses less digits than its factorization.

647761121280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 681 (or 643 counting only the distinct ones).

The product of its (nonzero) digits is 225792, while the sum is 45.

The spelling of 647761121280 in words is "six hundred forty-seven billion, seven hundred sixty-one million, one hundred twenty-one thousand, two hundred eighty".