66405564461 has 2 divisors, whose sum is σ = 66405564462. Its totient is φ = 66405564460.

The previous prime is 66405564457. The next prime is 66405564481. The reversal of 66405564461 is 16446550466.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 35191508836 + 31214055625 = 187594^2 + 176675^2 .

It is a cyclic number.

It is not a de Polignac number, because 66405564461 - 2² = 66405564457 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66405564451) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33202782230 + 33202782231.

It is an arithmetic number, because the mean of its divisors is an integer number (33202782231).

Almost surely, 2^66405564461 is an apocalyptic number.

It is an amenable number.

66405564461 is a deficient number, since it is larger than the sum of its proper divisors (1).

66405564461 is an equidigital number, since it uses as much as digits as its factorization.

66405564461 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2073600, while the sum is 47.

The spelling of 66405564461 in words is "sixty-six billion, four hundred five million, five hundred sixty-four thousand, four hundred sixty-one".