521666413 has 12 divisors (see below), whose sum is σ = 568728160. Its totient is φ = 477153936.

The previous prime is 521666407. The next prime is 521666443. The reversal of 521666413 is 314666125.

It is a de Polignac number, because none of the positive numbers 2^k-521666413 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521666443) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 345 + ... + 32302.

Almost surely, 2^521666413 is an apocalyptic number.

It is an amenable number.

521666413 is a deficient number, since it is larger than the sum of its proper divisors (47061747).

521666413 is a wasteful number, since it uses less digits than its factorization.

521666413 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32724 (or 32695 counting only the distinct ones).

The product of its digits is 25920, while the sum is 34.

The square root of 521666413 is about 22840.0177977164. The cubic root of 521666413 is about 805.0032344301.

The spelling of 521666413 in words is "five hundred twenty-one million, six hundred sixty-six thousand, four hundred thirteen".