2016661 has 4 divisors (see below), whose sum is σ = 2028492. Its totient is φ = 2004832.

The previous prime is 2016653. The next prime is 2016671. The reversal of 2016661 is 1666102.

2016661 = T₁₁₅₈ + T₁₁₅₉ + T₁₁₆₀.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1674436 + 342225 = 1294^2 + 585^2 .

It is a cyclic number.

It is not a de Polignac number, because 2016661 - 2³ = 2016653 is a prime.

It is a Duffinian number.

2016661 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2016671) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5656 + ... + 6001.

It is an arithmetic number, because the mean of its divisors is an integer number (507123).

2^2016661 is an apocalyptic number.

2016661 is the 1160-th centered triangular number.

It is an amenable number.

2016661 is a deficient number, since it is larger than the sum of its proper divisors (11831).

2016661 is a wasteful number, since it uses less digits than its factorization.

2016661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11830.

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 2016661 is about 1420.0918984347. The cubic root of 2016661 is about 126.3409970374.

The spelling of 2016661 in words is "two million, sixteen thousand, six hundred sixty-one".