520621668 has 216 divisors, whose sum is σ = 1683575712. Its totient is φ = 139781376.

The previous prime is 520621667. The next prime is 520621681. The reversal of 520621668 is 866126025.

520621668 is a `hidden beast` number, since 5 + 20 + 621 + 6 + 6 + 8 = 666.

It is a super-3 number, since 3×520621668³ (a number of 27 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (520621663) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 809355 + ... + 809997.

It is an arithmetic number, because the mean of its divisors is an integer number (7794332).

Almost surely, 2^520621668 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 520621668, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (841787856).

520621668 is an abundant number, since it is smaller than the sum of its proper divisors (1162954044).

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

520621668 is a wasteful number, since it uses less digits than its factorization.

520621668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 693 (or 672 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

The square root of 520621668 is about 22817.1354030255. The cubic root of 520621668 is about 804.4654800660.

The spelling of 520621668 in words is "five hundred twenty million, six hundred twenty-one thousand, six hundred sixty-eight".