66215858857751 has 8 divisors (see below), whose sum is σ = 66898799341584. Its totient is φ = 65532924552960.

The previous prime is 66215858857747. The next prime is 66215858857769. The reversal of 66215858857751 is 15775885851266.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 66215858857751 - 2² = 66215858857747 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66215858857721) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21809561 + ... + 24659453.

It is an arithmetic number, because the mean of its divisors is an integer number (8362349917698).

Almost surely, 2^{66215858857751} is an apocalyptic number.

66215858857751 is a deficient number, since it is larger than the sum of its proper divisors (682940483833).

66215858857751 is a wasteful number, since it uses less digits than its factorization.

66215858857751 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3089521.

The product of its digits is 1128960000, while the sum is 74.

The spelling of 66215858857751 in words is "sixty-six trillion, two hundred fifteen billion, eight hundred fifty-eight million, eight hundred fifty-seven thousand, seven hundred fifty-one".