66041537407661 has 4 divisors (see below), whose sum is σ = 66228623916252. Its totient is φ = 65854450899072.

The previous prime is 66041537407619. The next prime is 66041537407679. The reversal of 66041537407661 is 16670473514066.

It is a happy number.

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 12420056124100 + 53621481283561 = 3524210^2 + 7322669^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66041537407661 is a prime.

It is a super-2 number, since 2×66041537407661² (a number of 28 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 66041537407597 and 66041537407606.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66041537407861) 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, 93543253766 + ... + 93543254471.

It is an arithmetic number, because the mean of its divisors is an integer number (16557155979063).

Almost surely, 2^{66041537407661} is an apocalyptic number.

It is an amenable number.

66041537407661 is a deficient number, since it is larger than the sum of its proper divisors (187086508591).

66041537407661 is a wasteful number, since it uses less digits than its factorization.

66041537407661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 187086508590.

The product of its (nonzero) digits is 15240960, while the sum is 56.

The spelling of 66041537407661 in words is "sixty-six trillion, forty-one billion, five hundred thirty-seven million, four hundred seven thousand, six hundred sixty-one".