66964282523581 has 4 divisors (see below), whose sum is σ = 67042786958812. Its totient is φ = 66885778088352.

The previous prime is 66964282523563. The next prime is 66964282523587. The reversal of 66964282523581 is 18532528246966.

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 32601930236100 + 34362352287481 = 5709810^2 + 5861941^2 .

It is a cyclic number.

It is not a de Polignac number, because 66964282523581 - 2²⁹ = 66963745652669 is a prime.

It is a super-2 number, since 2×66964282523581² (a number of 28 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66964282523587) 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, 39252216336 + ... + 39252218041.

It is an arithmetic number, because the mean of its divisors is an integer number (16760696739703).

Almost surely, 2^{66964282523581} is an apocalyptic number.

It is an amenable number.

66964282523581 is a deficient number, since it is larger than the sum of its proper divisors (78504435231).

66964282523581 is an equidigital number, since it uses as much as digits as its factorization.

66964282523581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78504435230.

The product of its digits is 298598400, while the sum is 67.

The spelling of 66964282523581 in words is "sixty-six trillion, nine hundred sixty-four billion, two hundred eighty-two million, five hundred twenty-three thousand, five hundred eighty-one".