166220491 has 2 divisors, whose sum is σ = 166220492. Its totient is φ = 166220490.

The previous prime is 166220479. The next prime is 166220513. The reversal of 166220491 is 194022661.

166220491 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 is a cyclic number.

It is not a de Polignac number, because 166220491 - 2⁹ = 166219979 is a prime.

It is not a weakly prime, because it can be changed into another prime (166220591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83110245 + 83110246.

It is an arithmetic number, because the mean of its divisors is an integer number (83110246).

Almost surely, 2^166220491 is an apocalyptic number.

166220491 is a deficient number, since it is larger than the sum of its proper divisors (1).

166220491 is an equidigital number, since it uses as much as digits as its factorization.

166220491 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 166220491 is about 12892.6525975068. The cubic root of 166220491 is about 549.8296894166.

The spelling of 166220491 in words is "one hundred sixty-six million, two hundred twenty thousand, four hundred ninety-one".