521678916 has 216 divisors, whose sum is σ = 1561577472. Its totient is φ = 146361600.

The previous prime is 521678909. The next prime is 521678917. The reversal of 521678916 is 619876125.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (521678917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 4107645 + ... + 4107771.

Almost surely, 2^521678916 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 521678916, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (780788736).

521678916 is an abundant number, since it is smaller than the sum of its proper divisors (1039898556).

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

521678916 is a wasteful number, since it uses less digits than its factorization.

521678916 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 223 (or 207 counting only the distinct ones).

The product of its digits is 181440, while the sum is 45.

The square root of 521678916 is about 22840.2915042694. The cubic root of 521678916 is about 805.0096656633.

The spelling of 521678916 in words is "five hundred twenty-one million, six hundred seventy-eight thousand, nine hundred sixteen".