66666240 has 180 divisors, whose sum is σ = 238914984. Its totient is φ = 17750016.

The previous prime is 66666239. The next prime is 66666247. The reversal of 66666240 is 4266666.

It is a tau number, because it is divible by the number of its divisors (180).

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 = 66666195 and 66666204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66666247) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 103359 + ... + 104001.

Almost surely, 2^66666240 is an apocalyptic number.

66666240 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 66666240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (119457492).

66666240 is an abundant number, since it is smaller than the sum of its proper divisors (172248744).

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

66666240 is an equidigital number, since it uses as much as digits as its factorization.

66666240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 676 (or 653 counting only the distinct ones).

The product of its (nonzero) digits is 62208, while the sum is 36.

The square root of 66666240 is about 8164.9396813449. The cubic root of 66666240 is about 405.4792680121.

The spelling of 66666240 in words is "sixty-six million, six hundred sixty-six thousand, two hundred forty".