521780640 has 96 divisors (see below), whose sum is σ = 1666236096. Its totient is φ = 137226240.

The previous prime is 521780639. The next prime is 521780647. The reversal of 521780640 is 46087125.

It is a tau number, because it is divible by the number of its divisors (96).

It is not an unprimeable number, because it can be changed into a prime (521780647) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 27595 + ... + 42485.

It is an arithmetic number, because the mean of its divisors is an integer number (17356626).

Almost surely, 2^521780640 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 521780640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (833118048).

521780640 is an abundant number, since it is smaller than the sum of its proper divisors (1144455456).

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

521780640 is a wasteful number, since it uses less digits than its factorization.

521780640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14982 (or 14974 counting only the distinct ones).

The product of its (nonzero) digits is 13440, while the sum is 33.

The square root of 521780640 is about 22842.5182499653. The cubic root of 521780640 is about 805.0619861480.

The spelling of 521780640 in words is "five hundred twenty-one million, seven hundred eighty thousand, six hundred forty".