19681601 has 2 divisors, whose sum is σ = 19681602. Its totient is φ = 19681600.

The previous prime is 19681553. The next prime is 19681609. The reversal of 19681601 is 10618691.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12418576 + 7263025 = 3524^2 + 2695^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19681601 is a prime.

It is not a weakly prime, because it can be changed into another prime (19681609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9840800 + 9840801.

It is an arithmetic number, because the mean of its divisors is an integer number (9840801).

Almost surely, 2^19681601 is an apocalyptic number.

It is an amenable number.

19681601 is a deficient number, since it is larger than the sum of its proper divisors (1).

19681601 is an equidigital number, since it uses as much as digits as its factorization.

19681601 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2592, while the sum is 32.

The square root of 19681601 is about 4436.3950455296. The cubic root of 19681601 is about 269.9936029577.

The spelling of 19681601 in words is "nineteen million, six hundred eighty-one thousand, six hundred one".