66660042541 has 4 divisors (see below), whose sum is σ = 70581221532. Its totient is φ = 62738863552.

The previous prime is 66660042539. The next prime is 66660042551. The reversal of 66660042541 is 14524006666.

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 46878745225 + 19781297316 = 216515^2 + 140646^2 .

It is a cyclic number.

It is not a de Polignac number, because 66660042541 - 2¹ = 66660042539 is a prime.

It is a super-2 number, since 2×66660042541² (a number of 22 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 = 66660042494 and 66660042503.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66660042551) 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, 1960589470 + ... + 1960589503.

It is an arithmetic number, because the mean of its divisors is an integer number (17645305383).

Almost surely, 2^66660042541 is an apocalyptic number.

It is an amenable number.

66660042541 is a deficient number, since it is larger than the sum of its proper divisors (3921178991).

66660042541 is a wasteful number, since it uses less digits than its factorization.

66660042541 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3921178990.

The product of its (nonzero) digits is 207360, while the sum is 40.

The spelling of 66660042541 in words is "sixty-six billion, six hundred sixty million, forty-two thousand, five hundred forty-one".