19966601 has 2 divisors, whose sum is σ = 19966602. Its totient is φ = 19966600.

The previous prime is 19966591. The next prime is 19966613. The reversal of 19966601 is 10666991.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14899600 + 5067001 = 3860^2 + 2251^2 .It is also a bemirp because it and its reverse can be mirrored producing other two distinct primes, 10999661 and 16699901.

It is a cyclic number.

It is not a de Polignac number, because 19966601 - 2⁶ = 19966537 is a prime.

It is not a weakly prime, because it can be changed into another prime (19966621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9983300 + 9983301.

It is an arithmetic number, because the mean of its divisors is an integer number (9983301).

Almost surely, 2^19966601 is an apocalyptic number.

It is an amenable number.

19966601 is a deficient number, since it is larger than the sum of its proper divisors (1).

19966601 is an equidigital number, since it uses as much as digits as its factorization.

19966601 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 17496, while the sum is 38.

The square root of 19966601 is about 4468.4002730284. The cubic root of 19966601 is about 271.2905794160.

The spelling of 19966601 in words is "nineteen million, nine hundred sixty-six thousand, six hundred one".