16505261 has 2 divisors, whose sum is σ = 16505262. Its totient is φ = 16505260.

The previous prime is 16505213. The next prime is 16505267. The reversal of 16505261 is 16250561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11356900 + 5148361 = 3370^2 + 2269^2 .

It is a cyclic number.

It is not a de Polignac number, because 16505261 - 2¹⁴ = 16488877 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 16505261.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16505267) 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 as a sum of consecutive naturals, namely, 8252630 + 8252631.

It is an arithmetic number, because the mean of its divisors is an integer number (8252631).

Almost surely, 2^16505261 is an apocalyptic number.

It is an amenable number.

16505261 is a deficient number, since it is larger than the sum of its proper divisors (1).

16505261 is an equidigital number, since it uses as much as digits as its factorization.

16505261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1800, while the sum is 26.

The square root of 16505261 is about 4062.6667350399. Note that the first 3 decimals coincide. The cubic root of 16505261 is about 254.6092233206.

The spelling of 16505261 in words is "sixteen million, five hundred five thousand, two hundred sixty-one".