66501440 has 56 divisors (see below), whose sum is σ = 160641792. Its totient is φ = 26216960.

The previous prime is 66501403. The next prime is 66501451. The reversal of 66501440 is 4410566.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21257 + ... + 24183.

Almost surely, 2^66501440 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 66501440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (80320896).

66501440 is an abundant number, since it is smaller than the sum of its proper divisors (94140352).

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

66501440 is a wasteful number, since it uses less digits than its factorization.

66501440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3015 (or 3005 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 26.

The square root of 66501440 is about 8154.8415067370. The cubic root of 66501440 is about 405.1448752640.

The spelling of 66501440 in words is "sixty-six million, five hundred one thousand, four hundred forty".