66081413 has 4 divisors (see below), whose sum is σ = 66113388. Its totient is φ = 66049440.

The previous prime is 66081409. The next prime is 66081419. The reversal of 66081413 is 31418066.

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 57123364 + 8958049 = 7558^2 + 2993^2 .

It is a cyclic number.

It is not a de Polignac number, because 66081413 - 2² = 66081409 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 (66081419) 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, 12656 + ... + 17097.

It is an arithmetic number, because the mean of its divisors is an integer number (16528347).

Almost surely, 2^66081413 is an apocalyptic number.

It is an amenable number.

66081413 is a deficient number, since it is larger than the sum of its proper divisors (31975).

66081413 is a wasteful number, since it uses less digits than its factorization.

66081413 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31974.

The product of its (nonzero) digits is 3456, while the sum is 29.

The square root of 66081413 is about 8129.0474841767. The cubic root of 66081413 is about 404.2901001861.

Adding to 66081413 its reverse (31418066), we get a palindrome (97499479).

The spelling of 66081413 in words is "sixty-six million, eighty-one thousand, four hundred thirteen".