16549661 has 2 divisors, whose sum is σ = 16549662. Its totient is φ = 16549660.

The previous prime is 16549597. The next prime is 16549681. The reversal of 16549661 is 16694561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13764100 + 2785561 = 3710^2 + 1669^2 .

It is a cyclic number.

It is not a de Polignac number, because 16549661 - 2⁶ = 16549597 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16549681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8274830 + 8274831.

It is an arithmetic number, because the mean of its divisors is an integer number (8274831).

Almost surely, 2^16549661 is an apocalyptic number.

It is an amenable number.

16549661 is a deficient number, since it is larger than the sum of its proper divisors (1).

16549661 is an equidigital number, since it uses as much as digits as its factorization.

16549661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 38880, while the sum is 38.

The square root of 16549661 is about 4068.1274562137. The cubic root of 16549661 is about 254.8373228731.

The spelling of 16549661 in words is "sixteen million, five hundred forty-nine thousand, six hundred sixty-one".