66587248206781 has 4 divisors (see below), whose sum is σ = 66587537593564. Its totient is φ = 66586958820000.

The previous prime is 66587248206761. The next prime is 66587248206841. The reversal of 66587248206781 is 18760284278566.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 60131634382681 + 6455613824100 = 7754459^2 + 2540790^2 .

It is a cyclic number.

It is not a de Polignac number, because 66587248206781 - 2⁵ = 66587248206749 is a prime.

It is a super-3 number, since 3×66587248206781³ (a number of 42 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 66587248206781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66587248206761) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 144347970 + ... + 144808531.

It is an arithmetic number, because the mean of its divisors is an integer number (16646884398391).

Almost surely, 2^{66587248206781} is an apocalyptic number.

It is an amenable number.

66587248206781 is a deficient number, since it is larger than the sum of its proper divisors (289386783).

66587248206781 is a wasteful number, since it uses less digits than its factorization.

66587248206781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 289386782.

The product of its (nonzero) digits is 433520640, while the sum is 70.

The spelling of 66587248206781 in words is "sixty-six trillion, five hundred eighty-seven billion, two hundred forty-eight million, two hundred six thousand, seven hundred eighty-one".