521648810640 has 320 divisors, whose sum is σ = 1895637600000. Its totient is φ = 131486810112.

The previous prime is 521648810569. The next prime is 521648810647. The reversal of 521648810640 is 46018846125.

It is a happy number.

521648810640 is a `hidden beast` number, since 5 + 21 + 6 + 488 + 106 + 40 = 666.

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 (521648810647) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 18412806 + ... + 18441114.

It is an arithmetic number, because the mean of its divisors is an integer number (5923867500).

Almost surely, 2^521648810640 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 521648810640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (947818800000).

521648810640 is an abundant number, since it is smaller than the sum of its proper divisors (1373988789360).

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

521648810640 is a wasteful number, since it uses less digits than its factorization.

521648810640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28799 (or 28787 counting only the distinct ones).

The product of its (nonzero) digits is 368640, while the sum is 45.

The spelling of 521648810640 in words is "five hundred twenty-one billion, six hundred forty-eight million, eight hundred ten thousand, six hundred forty".