16666501 has 2 divisors, whose sum is σ = 16666502. Its totient is φ = 16666500.

The previous prime is 16666493. The next prime is 16666523. The reversal of 16666501 is 10566661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8820900 + 7845601 = 2970^2 + 2801^2 .

It is a cyclic number.

It is not a de Polignac number, because 16666501 - 2³ = 16666493 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (16666201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8333250 + 8333251.

It is an arithmetic number, because the mean of its divisors is an integer number (8333251).

Almost surely, 2^16666501 is an apocalyptic number.

It is an amenable number.

16666501 is a deficient number, since it is larger than the sum of its proper divisors (1).

16666501 is an equidigital number, since it uses as much as digits as its factorization.

16666501 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 16666501 is about 4082.4626146482. The cubic root of 16666501 is about 255.4356311155.

The spelling of 16666501 in words is "sixteen million, six hundred sixty-six thousand, five hundred one".