666543240 has 192 divisors, whose sum is σ = 2375568000. Its totient is φ = 160742400.

The previous prime is 666543239. The next prime is 666543247. The reversal of 666543240 is 42345666.

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

It is a junction number, because it is equal to n+sod(n) for n = 666543195 and 666543204.

It is not an unprimeable number, because it can be changed into a prime (666543247) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1112461 + ... + 1113059.

It is an arithmetic number, because the mean of its divisors is an integer number (12372750).

Almost surely, 2^666543240 is an apocalyptic number.

666543240 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 666543240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1187784000).

666543240 is an abundant number, since it is smaller than the sum of its proper divisors (1709024760).

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

666543240 is a wasteful number, since it uses less digits than its factorization.

666543240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 908 (or 901 counting only the distinct ones).

The product of its (nonzero) digits is 103680, while the sum is 36.

The square root of 666543240 is about 25817.4987169555. The cubic root of 666543240 is about 873.5265498465.

The spelling of 666543240 in words is "six hundred sixty-six million, five hundred forty-three thousand, two hundred forty".