166677038804821 has 2 divisors, whose sum is σ = 166677038804822. Its totient is φ = 166677038804820.

The previous prime is 166677038804807. The next prime is 166677038804923. The reversal of 166677038804821 is 128408830776661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 150043243617796 + 16633795187025 = 12249214^2 + 4078455^2 .

It is a cyclic number.

It is not a de Polignac number, because 166677038804821 - 2⁵ = 166677038804789 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (166677068804821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83338519402410 + 83338519402411.

It is an arithmetic number, because the mean of its divisors is an integer number (83338519402411).

Almost surely, 2^{166677038804821} is an apocalyptic number.

It is an amenable number.

166677038804821 is a deficient number, since it is larger than the sum of its proper divisors (1).

166677038804821 is an equidigital number, since it uses as much as digits as its factorization.

166677038804821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 130056192, while the sum is 67.

The spelling of 166677038804821 in words is "one hundred sixty-six trillion, six hundred seventy-seven billion, thirty-eight million, eight hundred four thousand, eight hundred twenty-one".