666416520 has 384 divisors, whose sum is σ = 2796768000. Its totient is φ = 133539840.

The previous prime is 666416503. The next prime is 666416539. The reversal of 666416520 is 25614666.

It is a happy number.

666416520 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×666416520² = 888221956257820800, which contains 22 as substring.

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

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 803466 + ... + 804294.

It is an arithmetic number, because the mean of its divisors is an integer number (7283250).

Almost surely, 2^666416520 is an apocalyptic number.

666416520 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 666416520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1398384000).

666416520 is an abundant number, since it is smaller than the sum of its proper divisors (2130351480).

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

666416520 is a wasteful number, since it uses less digits than its factorization.

666416520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 893 (or 886 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The square root of 666416520 is about 25815.0444508624. The cubic root of 666416520 is about 873.4711894471.

The spelling of 666416520 in words is "six hundred sixty-six million, four hundred sixteen thousand, five hundred twenty".