66724679024640 has 2688 divisors, whose sum is σ = 301121748373320. Its totient is φ = 14062121385984.

The previous prime is 66724679024639. The next prime is 66724679024657. The reversal of 66724679024640 is 4642097642766.

It is a happy number.

66724679024640 is a `hidden beast` number, since 6 + 6 + 7 + 2 + 467 + 90 + 2 + 46 + 40 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 53024494731264 + 13700184293376 = 7281792^2 + 3701376^2 .

It is a tau number, because it is divible by the number of its divisors (2688).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is an unprimeable number.

It is a polite number, since it can be written in 167 ways as a sum of consecutive naturals, for example, 76082871882 + ... + 76082872758.

Almost surely, 2^{66724679024640} is an apocalyptic number.

66724679024640 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 66724679024640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (150560874186660).

66724679024640 is an abundant number, since it is smaller than the sum of its proper divisors (234397069348680).

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

66724679024640 is an frugal number, since it uses more digits than its factorization.

66724679024640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 957 (or 907 counting only the distinct ones).

The product of its (nonzero) digits is 146313216, while the sum is 63.

The spelling of 66724679024640 in words is "sixty-six trillion, seven hundred twenty-four billion, six hundred seventy-nine million, twenty-four thousand, six hundred forty".