66335215521 has 16 divisors (see below), whose sum is σ = 89182368000. Its totient is φ = 43856226960.

The previous prime is 66335215511. The next prime is 66335215577. The reversal of 66335215521 is 12551253366.

It is not a de Polignac number, because 66335215521 - 2¹⁴ = 66335199137 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 66335215521.

It is not an unprimeable number, because it can be changed into a prime (66335215501) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 532806 + ... + 645408.

It is an arithmetic number, because the mean of its divisors is an integer number (5573898000).

Almost surely, 2^66335215521 is an apocalyptic number.

It is an amenable number.

66335215521 is a deficient number, since it is larger than the sum of its proper divisors (22847152479).

66335215521 is a wasteful number, since it uses less digits than its factorization.

66335215521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 114236.

The product of its digits is 162000, while the sum is 39.

Adding to 66335215521 its reverse (12551253366), we get a palindrome (78886468887).

The spelling of 66335215521 in words is "sixty-six billion, three hundred thirty-five million, two hundred fifteen thousand, five hundred twenty-one".