166839649221281 has 2 divisors, whose sum is σ = 166839649221282. Its totient is φ = 166839649221280.

The previous prime is 166839649221277. The next prime is 166839649221347. The reversal of 166839649221281 is 182122946938661.

166839649221281 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 118925219120656 + 47914430100625 = 10905284^2 + 6922025^2 .

It is a cyclic number.

It is not a de Polignac number, because 166839649221281 - 2² = 166839649221277 is a prime.

It is a super-2 number, since 2×166839649221281² (a number of 29 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (166839649221211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83419824610640 + 83419824610641.

It is an arithmetic number, because the mean of its divisors is an integer number (83419824610641).

Almost surely, 2^{166839649221281} is an apocalyptic number.

It is an amenable number.

166839649221281 is a deficient number, since it is larger than the sum of its proper divisors (1).

166839649221281 is an equidigital number, since it uses as much as digits as its factorization.

166839649221281 is an evil number, because the sum of its binary digits is even.

The product of its digits is 107495424, while the sum is 68.

The spelling of 166839649221281 in words is "one hundred sixty-six trillion, eight hundred thirty-nine billion, six hundred forty-nine million, two hundred twenty-one thousand, two hundred eighty-one".