66531413549 has 2 divisors, whose sum is σ = 66531413550. Its totient is φ = 66531413548.

The previous prime is 66531413471. The next prime is 66531413587. The reversal of 66531413549 is 94531413566.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 50406985225 + 16124428324 = 224515^2 + 126982^2 .

It is a cyclic number.

It is not a de Polignac number, because 66531413549 - 2¹² = 66531409453 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66531413849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33265706774 + 33265706775.

It is an arithmetic number, because the mean of its divisors is an integer number (33265706775).

Almost surely, 2^66531413549 is an apocalyptic number.

It is an amenable number.

66531413549 is a deficient number, since it is larger than the sum of its proper divisors (1).

66531413549 is an equidigital number, since it uses as much as digits as its factorization.

66531413549 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1166400, while the sum is 47.

The spelling of 66531413549 in words is "sixty-six billion, five hundred thirty-one million, four hundred thirteen thousand, five hundred forty-nine".