166305491 has 16 divisors (see below), whose sum is σ = 187060320. Its totient is φ = 146522880.

The previous prime is 166305481. The next prime is 166305497. The reversal of 166305491 is 194503661.

It is a cyclic number.

It is not a de Polignac number, because 166305491 - 2⁶ = 166305427 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166305497) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 128375 + ... + 129663.

It is an arithmetic number, because the mean of its divisors is an integer number (11691270).

Almost surely, 2^166305491 is an apocalyptic number.

166305491 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

166305491 is a deficient number, since it is larger than the sum of its proper divisors (20754829).

166305491 is a wasteful number, since it uses less digits than its factorization.

166305491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1654.

The product of its (nonzero) digits is 19440, while the sum is 35.

The square root of 166305491 is about 12895.9486273791. The cubic root of 166305491 is about 549.9233953915.

The spelling of 166305491 in words is "one hundred sixty-six million, three hundred five thousand, four hundred ninety-one".