666533620 has 96 divisors (see below), whose sum is σ = 1524096000. Its totient is φ = 243922944.

The previous prime is 666533611. The next prime is 666533627. The reversal of 666533620 is 26335666.

666533620 = 6659² + 6660² + ... + 6673².

It is a self number, because there is not a number n which added to its sum of digits gives 666533620.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666533627) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2988829 + ... + 2989051.

It is an arithmetic number, because the mean of its divisors is an integer number (15876000).

Almost surely, 2^666533620 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 666533620, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (762048000).

666533620 is an abundant number, since it is smaller than the sum of its proper divisors (857562380).

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

666533620 is a wasteful number, since it uses less digits than its factorization.

666533620 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 457 (or 455 counting only the distinct ones).

The product of its (nonzero) digits is 116640, while the sum is 37.

The square root of 666533620 is about 25817.3124085370. The cubic root of 666533620 is about 873.5223473855.

The spelling of 666533620 in words is "six hundred sixty-six million, five hundred thirty-three thousand, six hundred twenty".