66390381529 has 4 divisors (see below), whose sum is σ = 68679705060. Its totient is φ = 64101058000.

The previous prime is 66390381509. The next prime is 66390381557. The reversal of 66390381529 is 92518309366.

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 50242325904 + 16148055625 = 224148^2 + 127075^2 .

It is a cyclic number.

It is not a de Polignac number, because 66390381529 - 2¹⁹ = 66389857241 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (66390381509) 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, 1144661722 + ... + 1144661779.

It is an arithmetic number, because the mean of its divisors is an integer number (17169926265).

Almost surely, 2^66390381529 is an apocalyptic number.

It is an amenable number.

66390381529 is a deficient number, since it is larger than the sum of its proper divisors (2289323531).

66390381529 is a wasteful number, since it uses less digits than its factorization.

66390381529 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2289323530.

The product of its (nonzero) digits is 2099520, while the sum is 52.

The spelling of 66390381529 in words is "sixty-six billion, three hundred ninety million, three hundred eighty-one thousand, five hundred twenty-nine".