66243535440 has 160 divisors (see below), whose sum is σ = 212203084800. Its totient is φ = 17077063680.

The previous prime is 66243535387. The next prime is 66243535507. The reversal of 66243535440 is 4453534266.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 66243535392 and 66243535401.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7949196 + ... + 7957524.

It is an arithmetic number, because the mean of its divisors is an integer number (1326269280).

Almost surely, 2^66243535440 is an apocalyptic number.

66243535440 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 66243535440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (106101542400).

66243535440 is an abundant number, since it is smaller than the sum of its proper divisors (145959549360).

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

66243535440 is a wasteful number, since it uses less digits than its factorization.

66243535440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9445 (or 9439 counting only the distinct ones).

The product of its (nonzero) digits is 1036800, while the sum is 42.

The spelling of 66243535440 in words is "sixty-six billion, two hundred forty-three million, five hundred thirty-five thousand, four hundred forty".