16601661 has 12 divisors (see below), whose sum is σ = 24036480. Its totient is φ = 11041800.

The previous prime is 16601633. The next prime is 16601693. The reversal of 16601661 is 16610661.

It is not a de Polignac number, because 16601661 - 2¹¹ = 16599613 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16601261) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2386 + ... + 6236.

It is an arithmetic number, because the mean of its divisors is an integer number (2003040).

Almost surely, 2^16601661 is an apocalyptic number.

It is an amenable number.

16601661 is a deficient number, since it is larger than the sum of its proper divisors (7434819).

16601661 is a wasteful number, since it uses less digits than its factorization.

16601661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4336 (or 4333 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The square root of 16601661 is about 4074.5135906020. The cubic root of 16601661 is about 255.1039483934.

It can be divided in two parts, 1660 and 1661, that added together give a triangular number (3321 = T₈₁).

The spelling of 16601661 in words is "sixteen million, six hundred one thousand, six hundred sixty-one".