166003621 has 12 divisors (see below), whose sum is σ = 194884140. Its totient is φ = 140978880.

The previous prime is 166003597. The next prime is 166003633. The reversal of 166003621 is 126300661.

It can be written as a sum of positive squares in 2 ways, for example, as 82555396 + 83448225 = 9086^2 + 9135^2 .

It is not a de Polignac number, because 166003621 - 2⁷ = 166003493 is a prime.

It is a super-2 number, since 2×166003621² = 55114404370223282, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166003661) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10200 + ... + 20881.

It is an arithmetic number, because the mean of its divisors is an integer number (16240345).

Almost surely, 2^166003621 is an apocalyptic number.

It is an amenable number.

166003621 is a deficient number, since it is larger than the sum of its proper divisors (28880519).

166003621 is a wasteful number, since it uses less digits than its factorization.

166003621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31204 (or 31197 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 25.

The square root of 166003621 is about 12884.2392480115. The cubic root of 166003621 is about 549.5904620700.

The spelling of 166003621 in words is "one hundred sixty-six million, three thousand, six hundred twenty-one".