521680240 has 20 divisors (see below), whose sum is σ = 1212906744. Its totient is φ = 208672064.

The previous prime is 521680223. The next prime is 521680249. The reversal of 521680240 is 42086125.

It is a tau number, because it is divible by the number of its divisors (20).

It is a junction number, because it is equal to n+sod(n) for n = 521680199 and 521680208.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521680249) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3260422 + ... + 3260581.

Almost surely, 2^521680240 is an apocalyptic number.

It is an amenable number.

521680240 is an abundant number, since it is smaller than the sum of its proper divisors (691226504).

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

521680240 is a wasteful number, since it uses less digits than its factorization.

521680240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6521016 (or 6521010 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 28.

The square root of 521680240 is about 22840.3204881193. The cubic root of 521680240 is about 805.0103466901.

The spelling of 521680240 in words is "five hundred twenty-one million, six hundred eighty thousand, two hundred forty".