66561636340029 has 4 divisors (see below), whose sum is σ = 88748848453376. Its totient is φ = 44374424226684.

The previous prime is 66561636340013. The next prime is 66561636340079. The reversal of 66561636340029 is 92004363616566.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 66561636340029 - 2⁴ = 66561636340013 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66561636340079) 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, 11093606056669 + ... + 11093606056674.

It is an arithmetic number, because the mean of its divisors is an integer number (22187212113344).

Almost surely, 2^{66561636340029} is an apocalyptic number.

It is an amenable number.

66561636340029 is a deficient number, since it is larger than the sum of its proper divisors (22187212113347).

66561636340029 is a wasteful number, since it uses less digits than its factorization.

66561636340029 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22187212113346.

The product of its (nonzero) digits is 25194240, while the sum is 57.

The spelling of 66561636340029 in words is "sixty-six trillion, five hundred sixty-one billion, six hundred thirty-six million, three hundred forty thousand, twenty-nine".