521378647860 has 192 divisors, whose sum is σ = 1738956570624. Its totient is φ = 114208012800.

The previous prime is 521378647847. The next prime is 521378647861. The reversal of 521378647860 is 68746873125.

It is a self number, because there is not a number n which added to its sum of digits gives 521378647860.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521378647861) 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, 1146670 + ... + 1535450.

It is an arithmetic number, because the mean of its divisors is an integer number (9057065472).

Almost surely, 2^521378647860 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 521378647860, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (869478285312).

521378647860 is an abundant number, since it is smaller than the sum of its proper divisors (1217577922764).

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

521378647860 is a wasteful number, since it uses less digits than its factorization.

521378647860 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 388934 (or 388932 counting only the distinct ones).

The product of its (nonzero) digits is 13547520, while the sum is 57.

The spelling of 521378647860 in words is "five hundred twenty-one billion, three hundred seventy-eight million, six hundred forty-seven thousand, eight hundred sixty".