166621663 has 24 divisors (see below), whose sum is σ = 187230960. Its totient is φ = 148112640.

The previous prime is 166621661. The next prime is 166621673. The reversal of 166621663 is 366126661.

It is not a de Polignac number, because 166621663 - 2¹ = 166621661 is a prime.

It is a Smith number, since the sum of its digits (37) coincides with the sum of the digits of its prime factors.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166621661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 963045 + ... + 963217.

It is an arithmetic number, because the mean of its divisors is an integer number (7801290).

Almost surely, 2^166621663 is an apocalyptic number.

166621663 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

166621663 is a deficient number, since it is larger than the sum of its proper divisors (20609297).

166621663 is a wasteful number, since it uses less digits than its factorization.

166621663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 379 (or 366 counting only the distinct ones).

The product of its digits is 46656, while the sum is 37.

The square root of 166621663 is about 12908.2013851659. The cubic root of 166621663 is about 550.2716707457.

The spelling of 166621663 in words is "one hundred sixty-six million, six hundred twenty-one thousand, six hundred sixty-three".