16251661 has 2 divisors, whose sum is σ = 16251662. Its totient is φ = 16251660.

The previous prime is 16251647. The next prime is 16251679. The reversal of 16251661 is 16615261.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 10989225 + 5262436 = 3315^2 + 2294^2 .

It is a cyclic number.

It is not a de Polignac number, because 16251661 - 2⁹ = 16251149 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16251691) 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, 8125830 + 8125831.

It is an arithmetic number, because the mean of its divisors is an integer number (8125831).

Almost surely, 2^16251661 is an apocalyptic number.

It is an amenable number.

16251661 is a deficient number, since it is larger than the sum of its proper divisors (1).

16251661 is an equidigital number, since it uses as much as digits as its factorization.

16251661 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2160, while the sum is 28.

The square root of 16251661 is about 4031.3348905790. The cubic root of 16251661 is about 253.2984807009.

The spelling of 16251661 in words is "sixteen million, two hundred fifty-one thousand, six hundred sixty-one".