16510661 has 4 divisors (see below), whose sum is σ = 16680972. Its totient is φ = 16340352.

The previous prime is 16510643. The next prime is 16510699. The reversal of 16510661 is 16601561.

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 4330561 + 12180100 = 2081^2 + 3490^2 .

It is a cyclic number.

It is not a de Polignac number, because 16510661 - 2⁶ = 16510597 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 16510661.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16510261) 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 3 ways as a sum of consecutive naturals, for example, 85010 + ... + 85203.

It is an arithmetic number, because the mean of its divisors is an integer number (4170243).

Almost surely, 2^16510661 is an apocalyptic number.

It is an amenable number.

16510661 is a deficient number, since it is larger than the sum of its proper divisors (170311).

16510661 is an equidigital number, since it uses as much as digits as its factorization.

16510661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 170310.

The product of its (nonzero) digits is 1080, while the sum is 26.

The square root of 16510661 is about 4063.3312687990. The cubic root of 16510661 is about 254.6369869913.

It can be divided in two parts, 16510 and 661, that added together give a palindrome (17171).

The spelling of 16510661 in words is "sixteen million, five hundred ten thousand, six hundred sixty-one".