166678957541 has 2 divisors, whose sum is σ = 166678957542. Its totient is φ = 166678957540.

The previous prime is 166678957517. The next prime is 166678957559. The reversal of 166678957541 is 145759876661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 163046364100 + 3632593441 = 403790^2 + 60271^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166678957541 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166678957241) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83339478770 + 83339478771.

It is an arithmetic number, because the mean of its divisors is an integer number (83339478771).

Almost surely, 2^166678957541 is an apocalyptic number.

It is an amenable number.

166678957541 is a deficient number, since it is larger than the sum of its proper divisors (1).

166678957541 is an equidigital number, since it uses as much as digits as its factorization.

166678957541 is an evil number, because the sum of its binary digits is even.

The product of its digits is 76204800, while the sum is 65.

The spelling of 166678957541 in words is "one hundred sixty-six billion, six hundred seventy-eight million, nine hundred fifty-seven thousand, five hundred forty-one".