666485820 has 576 divisors, whose sum is σ = 2835495936. Its totient is φ = 126904320.

The previous prime is 666485737. The next prime is 666485821. The reversal of 666485820 is 28584666.

It is a super-2 number, since 2×666485820² = 888406696522144800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666485821) by changing a digit.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 4864792 + ... + 4864928.

It is an arithmetic number, because the mean of its divisors is an integer number (4922736).

Almost surely, 2^666485820 is an apocalyptic number.

666485820 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 666485820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1417747968).

666485820 is an abundant number, since it is smaller than the sum of its proper divisors (2169010116).

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

666485820 is a wasteful number, since it uses less digits than its factorization.

666485820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 192 (or 178 counting only the distinct ones).

The product of its (nonzero) digits is 552960, while the sum is 45.

The square root of 666485820 is about 25816.3866565405. The cubic root of 666485820 is about 873.5014655349.

The spelling of 666485820 in words is "six hundred sixty-six million, four hundred eighty-five thousand, eight hundred twenty".